Here are some of my suggestions, I haven't read all the existing ones so some might have been suggested already.
1. Adding a keychain or a way to sort the generous amount of keys we loot (or maybe once we used the key for its proper chest it could self-destroy?
2. Adding a button to compact the inventory
3. Sneaking mechanics are toned down way too much ==> way too easy to go around stealing stuff in the first town. Having 0 point into stealth, my fighter should not be stealthing inside every buildings stealing all the ornaments and opening all the chests.
Which brings me to tip 4
4. Making the chest keys harder to find. I understand it's the starting town but they are not even hidden anywhere. All you have to do is enter a building/cellar/whatever and hold down your toggle key to view the items on the ground and voila
5. Adding an option to make the combat movement animations slightly faster. Games with turn-based combat usualy have this option which makes the replayability of the game much more enjoyable.
6. Remove the godly 2H axe from the cook's house that allows my level 3 character to solo group of 5 monsters his level
