The 3rd Edition hexblade sucked, to say the least. From what I recall, it was a hybrid class that attempted to mix martial swordplay with a pittance of arcane practice to create a sub-par fusion of incompetence. It's key ability was to impose a generic curse upon an opponent, that would penalize them in some fashion for baaasically the entire battle.
This hexblade is a melee-oriented arcane striker that comes with a built-in pact weapon, that she can form out of raw, arcane energy. They're proficient with chainmail, can use all simple and military melee weapons (and simple ranged if you give two fucks), in addition to rods and wands. All of the 1st-level infernal stuff is previewed with the exception of daily spells, which is fine because I prefer devils to faeries anyway.
- This time around, eldritch bolt is the new blast. It's still keyed to Charisma and deals the same damage, but its force instead of untyped. Infernal hexblades can conjure the blade of annihilation, which aside from sounding badass, is a heavy blade that gets +2 to attack and deals 1d12 damage. The best part? It's one-handed.
- Like warlock pacts you get an attack based on your pact, in this case soul eater, which is a Charisma-based melee attack that deals necrotic damage and gives you a bonus on the next attack you make against the same critter.
- There's also a previewed encounter spell, blazing doom of the void. It's also Charisma based, but deals double-weapon damage and gives you a hefty damage bonus against the next attack you make.
- Infernal Pact Reward grants you a bonus to all damage rolls equal to your Constitution modifier.
- The last class feature previewed is level nine's Summon Warlock's Ally, which in the case of infernal hexblades is a spined devil lackey that grants a bonus to Intimidate checks and can make ranged attacks with its quills. I can't tell if its a daily or what, but it might be a similar to a familiar or spirit companion.