What's the codex consensus!
Better stuff:
Pawn AI is less customizable but learns more intelligent behaviour.
Lots of skills have been folded into the core move sets for each vocation.
Fighting big creatures is far more fun (less reliance on climbing for some vocations, improved climbing control/camera for those that do)
More interesting variety of vocations with more clearly defined roles
There are less times when I felt like I wasn't able to hurt monsters due to weapon/level gap
No loli pawns.
Big creature move sets are more interesting
map is much bigger and has a much wider variety of biomes
Unmoored World
Stuff I miss:
Night time being more dangerous
Big dungeons
Bitterblack Isle
Some of the art design/aesthetic, especially area design
The atmosphere generally felt more oppressive/suspenseful in DDDA
Monster variety
Hard mode
Some of the weapons and armour sets can look pretty goofy
Stuff I don't miss that much but other people do:
Fewer active abilities (having more folded in base abilities makes this less impactful- except for Mages/Sorcerers who are at a disadvantage)
Layered armour.
Customisable Pawn AI.
I've probably forgotten some other points.
Overall, I like both games but at the moment I think DDDA has more replayabllity due to its higher difficulty, but if I was going to choose to play through one of them once, I'd go for DD2, which I think has the basis to be a better game if the expansion delivers.