Some of these might qualify as Divinity 2 ("I wish this was in the game"), but...
1) Summon Mastery should also increase the number of summons you can have out at once. One summon at Rank 1 and 2, two summons at Rank 3 and 4, three summons at rank 5 (or two summons at rank 2 and 3 and three at rank 4 and 5). That would make a summoner build more useful.
2) If the next game features skill re-trainers and illusionists, there should be ones in the starting village or nearby. I'm sure I mentioned this before in one of these threads. If you mess your build up there's no fixing it until a later which may not come (especially since even well-built characters can have trouble in some mandatory parts).
3) I'm sure I also mentioned this in a similar thread, but it would be nice that for the bounty hunter quests where you need to turn in something equippable, it would be nice if you could select that item from among the optional rewards. It could even be more complex - you could bargain with some of the bounties - you show the champions the item you need to turn in, get the bounty and reward and split the bounty with the target. If you do lie about the target getting killed, you could then go back and optionally double-cross the target just for fun!
