May be a little late to get any of these requests onto the release... but hey, my wish list.
A bag of holding please to stop needless visits to that container you stuffed full of items that you might just need again (Mine is usually the container on the first floor of the Friendly Arm Inn). Quivers, Belts and Scroll cases are also useful.
Quivers that supply endless amounts of +1 arrows exist. How about scroll cases that supply endless amounts of a particular scroll? Should restrict this to lvl1 or 2 spells but could be useful to have. Lots grease spells could be cool to use etc... A similar option could be for potion cases supplying endless healing potions... Maybe too overpowered.
A seperate spawn setting. You have a difficulty setting that effects the rules. How about a spawn setting that sets how many monsters you fight? A person who wants to play pure DnD ruleset may capitulate when the monsters come thick and fast. However give them the option to thin em out a bit... Alternatively give your sword arm more of a work out with maxo spawns! When you positively, absolutely need to kill a screenful of monsters...
Move Boo out of Minsc's potion quick use slots and into his backpack. Let Minsc have his healing potion and drink it please... Boo is usually eating eyes anyway... While were at it, make Minsc properly bald. That white fuz he had put me off my food.
Give Jaheria a sense of humour.
Make Saveoursock meaner. He wes too easy as I recall. Maybe make Saveoursock a little more canny and send you on quests (In his disguised form you meet at Candlekeep maybe? Who knows how many Bhaalspawns Gorion brought back to candlekeep for safe keeping) to kill other Bhaalspawns... Saveoursock will think he will be getting rid of two Bhaalspawns for the price of one... heh!
Give Xvarts machine guns. Perhaps maybe give them a bunker or a trench to hide behind. It would have been more useful than that teddy bear and that nuclear fall out shelter... That shelter looked like a cave! It was full of bats!
Extra depravity as well please. Everyone loves a good bit of depravity...