Baldur's Gate III - Spoiler Edition (please read updated OP)

I really liked it, but there are certainly things about it that I think could have been improved.  Fortunately, it looks like most of those will be different anyway.

1.  It has a very steep level/item progression.  It's pretty hard going up against anything more than a level higher than you first time round and it takes a lot of item management and buying/selling to even half keep up with the gear.  I did like the system of getting new skills through books though.  D&D obviously has a completely different leveling system and apparently 5th edition is designed so magic items aren't really necessary.  I expect there will still be plenty, as looting better gear is arguably even more a part of video games than tabletop, but I don't expect nearly as much need to upgrade all the time.  Not to mention there's quite a lot about leveling that's far from obvious without looking up a guide.

2.  That leveling system also reduced the flexibility you have.  You really shoot yourself in the foot if you don't complete as much as possible in each act, and you need to do a lot in a sensible order to avoid hitting a brick wall.  Although you can approach many things a number of ways, you don't really get a very different experience of the story on different play throughs except the parts that relate to your party.  Or maybe I just didn't play differently enough?   From what the devs have said, in BG there will be branching paths through the main story and you can completely skip (or maybe not even find) whole areas.  That's what interests me the most as not many games pull it off.  I hope they can.

3.  The maps feel very compact, particularly the Reaper's coast (the biggest act of the game).  It doesn't give a great sense of scale.  I don't mind that for the game it is, but in the BG gameplay we've seen, everything seems more realistically spread out and much more grand.  Just the abandoned village and the goblin camp look like pretty sizable areas.  I only hope they're not as densely packed with loot, or I'll never get anywhere due to OCD.

4.  The cartoony art style never bothered me, but I prefer the more realistic look of BG.