I'd like to have an option to turn off the "bump up item" the inventory does. I want to organize all the items on the "All" like I want so I won't have to go to specific pages to find what I'm looking for. If I put an item in the bottom corner I'd like it to stay there even though there is an empty space between it and the other items.
I would also like an "All non-quest items" page. That's obviously not a big deal if the first suggestion is implemented.
An option to increase the "split stack" bar. Even better an option to type in how many stacks you want to split.
Bartering having a value indicator on each side. I'd like to know exactly how much my side is worth compared to that of the trader's.
An option to store items in containers or item piles by double-clicking, same way it works with traders.
Inventory should automatically close when you finish or cancel a transaction with a trader.