The aberrant/aberration category includes most of my favorite monsters; mind flayers, intellect devourers, beholders, grells, aboleths, chuuls, fell taints (despite the name), mutated/warped things, and more. I am a huge fan of Lovecraft's works, my second long-term 4th Edition D&D campaign took place in Eberron's Shadow Marches, involving a number of star cults trying to summon an aberrant star, and one of my first 5th Edition homebrews were conversions of those very cultists.
In short I really, really dig this sort of thing.
For me the aberrant/aberration definition is spot on. In the game Eternal Darkness there is a part where you play a character who can perform autopsies on the creatures you kill. A lot of the descriptions are great, but I distinctly remember the one concerning a creature that looked like two headless humanoid bodies fused at the waist, where he makes mention of the corpse's anatomy making no sense (a lack of organs will do that).
I like the mention of psionics--which will hopefully not take a year or two to see the light of day--though I have nothing against some sort of sanity-stripping magic system, especially for the warlock and options like the alienist prestige class/paragon path.
The concept of the Far Realm is something I was pleased to see in 4th Edition, though I was disappointed that it never really got elaboration. I get the reasons for wanting to avoid making certain things official or assumed in everyone's campaign, but it would be great to finally have one or more optional planes get some decent page-space this time around (not that every aberrant critter needs to have other-worldly origins).
Given that my group virtually never breaches the first 10 levels in any edition, beholders are not something we have a lot of experience with. Despite this we are still very well aware of their eye rays (especially the save-or-die ones), so having a variation among eye rays could be nice for mixing things up and keeping characters on their toes. I also like the variation in size and appearance. The gauth is nice for giving low-level parties a taste of eye-ray volleys, while the hive mother allowed you to challenge epic characters. I also liked the DiTerlizzi drawings in 2nd Edition's Monster Manual (especially the one with crab pincers for some reason).
|Beauty is in the eye of the beholder and all that.|
The mind flayer is in my top ten favorite monsters, and the description is spot on with my expectations; tentacles, mind blast, domination, thralls, eats brains, ceremorphosis...basically everything that you would expect. I like the mention of psionics (crystals or no), which I take to mean that the initial version will not use spell-like abilities.
I am hopeful that the flat math will prevent low-power thralls like orcs, bugbears, and grimlocks from being too weak to threaten the characters without having to inflate their Hit Dice or lump on class levels.
Finally, I am curious as to if/how/when they will integrate past content, such as thoon (including both illithid disciples and the machines), neothelids, alhoon (ie, illithi-liches), and whatever those illithids with really long tentacles were called.
I have only ever used an aboleth once, and that was when we were playing A Sundered World so I did not use it "officially", though they also rank among my favorites. As with mind flayers they are pretty much what I expect, and again I hope that the flat math will make it easier to employ low-level threats without disrupting encounter difficulty one way or the other.
Aside from 3rd Edition's Lords of Madness I do not recall much flavor content pertaining to them, but I like the potential plot hooks that their genetic memory (and, to a point, their ability to go dormant) allows for.
Now that I am chomping at the bits to run a campaign another brimming with eldritch horrors from beyond space and time, hopefully we get some quality, insanity inducing aberrant art tomorrow.