As far as I could tell nothing has changed mechanically, which is fine for me as the only thing I do not like is how resistance is treated in Next. I suppose humans could stand to have a more definitive trait than a boost to every ability score (I really liked the bonus skill and feat they got before).
Backgrounds & Skills
The skill list seems the same as before, but rather than have a static modifier skills now require you to roll a skill die. It starts at a d4 and eventually caps out at a d12. At first I thought this was interesting idea, because I assumed that you would have the option to boost a die at various levels like how you could add a +1 to any skill in the previous packet release.
Not so. Everyone uses the same die at a given level, across the board, and for better or for worse if you spend a feat on Superior Skill Training they all use the skill die for whatever level you are at, despite just picking the skill up. Different, but I preferred having to make a choice when increasing a skill.
Specialties & Feats
First things first, I am glad to see that Specialist suffix go away. So instead of Ambush Specialist, you just have Ambusher. Maybe not as inspiring, but at least it rolls of the tongue more easily.
Some feats do not make a lot of sense name-wise, like Combat Superiority, which lets you hit a creature after protecting an ally with Shield Bash, which not only deals no damage but instead imposes disadvantage when an adjacent enemy attacks an ally. Also, I am kind of confused as to why there is a Superior Skill Training feat when there is no run-of-the-mill Skill Training feat.
Names aside they at least do more than just give you +1 to this or that. Even Improved Initiative gives you a bonus and lets you treat a 10 or less as a 10. There are also some new feats, like Called Shot, which lets you use the Disarm maneuver as a ranged attack and forego an attack to make an automatic crit on the following turn. Purge Magic is also kind of neat; you can cast dispel magic a number of times per day based on your Intelligence or Wisdom mod.
My overall impression of classes is that they all around look better to various degrees, but there are a lot of dead levels that could stand to be filled in.
The cleric is looking a lot better. There are three new deity archetypes--the Arcanist, Reaper, and Stormcaller--and I dig that each deity entry mentions gods from both Dungeons & Dragons and real-world mythology (examples are always handy).
Your deity choice, in addition to determining your starting at-wills/cantrips/orisons, also determines your starting proficiencies (as they now start with no armor proficiencies) and what Channel Divinity does. After so many editions of clerics touring about in heavy armor, I am going to take a stab at an Arcanist cleric who is shielded by mage armor instead of chainmail, and channels her divine might to boost the wizard spells that she also has access to.
Speaking of channeling divine might, Channel Divinity is more like 4th Edition now in that there are a variety of options to choose from. Instead of just being able to heal or hurt things with pulses of positive and negative energy, for example, the Warbringer lets you use it to Channel Strength (gain advantage on a melee attack or Strength check) and Channel Wrath (deal bonus damage).
The only thing I really do not like about it is that every cleric gets Combat Expertise at 6th-level. Aside from the fact that I find it odd that all clerics, regardless of combat prowess, get it at the same time (and it scales at the same rate), it needlessly references the Weapon Attack Bonus, Martial Damage Dice, and Martial Damage Bonus--the latter of the two I will touch on more in a bit--columns that you would already see if you actually looked at the table.
I know it would be a bit more complicated, but I think that the various deities should just give you these things at differing levels, because as its stands both the Arcanist and Warbringer cleric have the same chance of hitting a monster in melee. The only difference is that the Warbringer can use other weapons and burn Channel Divinity to occasionally be more reliable with it.
The fighter now gains Parry as a default class feature, and instead of Deadly Strike just has the default ability to spend
Besides the name change, the other major thing is that all MDD are d6's, and the fighter gets less of them (capping out at 6d6 at level 11). To offset this they also have a Martial Damage Bonus, which is a once-per-turn scaling bonus to damage. It starts out at +5 at 7th-level, eventually peaking at +20 at 17th-level.
There is a major shift in the class at 11th-level, where the fighter stops gaining maneuvers (the last one gained at 10th-level, for a total of 5) and instead gains Combat Surge, which is a per-day ability that lets them take another action.
On the upside, monks have four Monastic Traditions to choose from: the Path of Mercy, Pheonix, Four Storms, or Stone's Endurance. On the downside all these do is determine which ki-fueled powers you get, though granted many of them are pretty cool: Vengeful Flame lets you spend ki when you are dropped to deal 20 fire damage to up to three creatures within 40 feet of you, plus another 20 per use of ki you have left over, while Vortex Punch lets you conjure whirlwinds after you hit a creature, which follows a 50-foot line and knocks creatures out of the way unless they make Strength saves.
Barring an actually effective flurry of blows (despite a three-punch limit), the class has a lot of 3rd Edition stuff built in; Diamond Body, Abundant Step, Quivering Palm, etc. I am kind of disappointed with this, as I would have liked to see more diverse class features thematic to a particular tradition or playstyle. Well, except for maybe their level 20 ability, Perfect Self. Giving yourself a 20 in every stat is something most any monk could use. Hopefully we will see more of this stuff later on.
While rogues have Martial Damage Dice and a Martial Damage Bonus, they no longer gain maneuvers. Instead they have skill tricks, which let them do things like add skill dice to things that you normally would not (like saving throws), forego rolling a skill die when making a check for some other effect, or something else entirely.
For example, Feint lets you use an action to spend your skill die in order to make a Charisma contest against a creature's Wisdom. If you win, the next attack against it has advantage. Gilded tongue simply lets you spend your skill die to reroll a Charisma check, while Quick Reflexes lets you add your skill die to an Initiative check, or spend it when surprised to negate the surprise.
Rogue schemes have been greatly expanded to include things like Acrobat, Assassin, and Scout. These can grant you rogue talents, like Artful Dodger, which lets you use a reaction impose disadvantage on a melee or ranged attack made against you, or Sneak Attack, which lets you sack your attack advantage to double your Martial Damage Dice results.
The assassin is unique in that it also grants you access to all martial weapons and shields. It also comes with Assassinate, which lets you make a max-damage attack against a target that is potentially doubled if it fails a Constitution save.
Like the fighter the rogue sees a noticeable shift at 11th-level, capping out on skill tricks and instead only gaining uses of Ace in the Hole. This per-day ability lets you turn a miss into a hit, or a failed skill check or saving throw into an unnatural 20.
Wizards get a pretty big shake-up, what with their more flexible "cleric-ized" magic system. You prepare a number of spells equal to 1 + your wizard level, and can cast them in any combination up to a level-based cap. It is more forgiving because you are much less likely to prep the "wrong" spells, or not prepare enough of the "right" ones, but ultimately still makes no sense.
What is a spell slot? Is it representative of your mind's spells-storing capacity? A measure of the amount of mental stress you can endure? The amount of mana you possess (or some other form of magical energy)? Why can you use higher level slots to cast a lower-level spell, but no amount of low-level slots can be used to fuel a higher level one?
There are still three traditions, though one is a generic wizard and the other two are school-based. Scholarly Wizardry is really nice: you get any four cantrips you want (other traditions force you to pick one from a specific school), start with more 1st-level spells, can prep more, and gain twice as many with each level up. It mentions Ritual Caster on the list, but by default wizards in general can do that anyway so I am not sure why it is there.
School of Evocation lets you ignore creatures in an area-effect attack based on the spell's level, grants energy resistance, and 1's on damage dice get treated as 2's. The downside, in addition to the sheer lack of spells that Scholarly Wizards get, is that you have to pick an Evocation cantrip. School of Illusion gives you better save DC's, advantage against illusions, and lets you detect invisible critters. Similar to Evocation, you have to take an illusion cantrip.
I like that spells are more flexible and the traditions seem better than before, but the class is still held back by a lack of interesting and explainable magic.
There are some new armor types, most notably mithral armors for each category. They basically serve as a category capstone, either eking out another bit of AC bonus, or removing either Stealth disadvantage or a Speed penalty. I still think that Light armor and a good Dexterity is still too easy to achieve, and that both Medium and Heavy armor needs some sort of incentive like damage resistances.
Weapons now come in Simple, Martial, and Special flavors. Finesse is a property rather than a sub-category. There is also a Heavy property, which Small creatures can use but take disadvantage with. Versatile is back, but only for the bastard sword; the weapon has two damage values depending on how many hands you are using.
Special weapons are like exotic weapons from 3rd Edition, in that they require special training (read: feats) to use properly and are pretty underwhelming. I mean, who would not want to spend a feat in order to gain a Reach weapon that deals a flat 1d4 damage? I do not understand why they do not go with the 4th Edition treatment, when they were actually worth the feat.
Oh, double weapons are back. Love them or hate them, at least they do not cost feats.
As I have already mentioned, rogues no longer have their own list of maneuvers, though Bull Rush and Trip have been moved into a General Maneuvers category (along with Precise Shot and Rapid Shot). These exist to allow non-fighters and monks to spend their MDD to do other things besides boost damage. In a surprising twist, both Bull Rush and Trip are easy to resolve; each die you spend on a Bull Rush just pushes the target back 5 feet, and you can spend a MDD after hitting the target to just knock it prone (you can spend more dice to knock a bigger creature prone, too).
Obviously there are a lot more spells to choose from, including classics like gate, meteor swarm, true resurrection, and wish. The damage from cantrips now automatically scales with level, making them more useful later on. Actually most if not all damaging spells scale if you prep them using higher-level spell slots. A lot more spells can be used as rituals, and though while specific components are mentioned there are not any hard gp costs.
Other than that the spells are typical D&D fare, divvied up over the course of nine levels (though as I asked before what a spell level means is anyone's guess), with some of the higher-level stuff being just improved versions of the lower-level stuff (some of which have a Greater prefix). On that note, why do only damaging spells have an increased effect when cast with a higher level slot? This would be a perfect opportunity to give us, say, a dispel magic spell that can dispel spells based on the slot you cast it with instead of giving us dispel magic and greater dispel magic.
Another point of contention is gem-dust. Why does it matter how much a diamond was worth if all you are going to do is crush it up, anyway? Does magic really care how pretty it is? If not, then why not just specify a weight? Why does gate require diamond dust, anyway? What if the caster wants to open up a portal to the Nine Hells? Would not ground up rubies make more sense (or rubies and like, iron filings)? Why is not gate a ritual? Opening a portal between planes seems like something that would take more time than six seconds to do.
Finally, while I like that true names are being included to a point, it seems like a shallow implementation and I think it is silly that you can only use a truename once before you have to learn it all over again. I guess it kind of made sense in The Dresden Files, where mortals reinvent themselves constantly, but not so much for extraplanar beings.
All in all I think the magic system technically works as is, purely as a game mechanic. It is still, after all these playtest iterations, not particularly imaginative, engaging, or sensible.
The stat block is still unchanged. Some monster sizes seemed to have been changed at random; rocs are now Gargantuan, flesh golems are Medium, giants are Huge. Given the minis that I and many others have accumulated over the years, this seems like a bad idea (especially for DMs wanting to run adventures with lots of giants).
None of the monsters have descriptions, which is problematic given that I only know the amphisbaena snake has because its Hardened Corpse trait--which actually sounds kind of cool--makes mention of more than one head. Similarly though an automaton makes four scythe attacks, I have no idea what it is supposed to look like. Does it attack really fast with two scythes? Does it have four? Does it look humanoid, or does it look like the insect-like slaughterstone behemoth?
On the plus side there are a lot of new monsters, including a lich, rakshasa, vampire, high-level dragons, demons, and devils, more giants, some golems, and more. Basically the solid foundation of the roster you would expect from a Monster Manual. Also, according to the Read First pdf stats and XP has been changed, though I will need to read through the Bestiary more thoroughly.