I agree with what Kohaku said.
Trade Screen is the most tedious to use part of the UI atm. One caravan can easily have hundreds of items and browsing it all with the current UI is a real pain. Any sort of sorting / grouping / filtering / mass selecting would be great.
The "Bring items to Depot" screen is quite good already and is a nice example - has 2 sorting options, grouping and filtering by string.
Hopefully equipment / military bugs will get fixed. These are the most annoying bugs in current version and they are scoring rank #1 in worst bugs vote for quite some time.
It may be quite complex as there are legions of subbugs (#535 is with 31 open children).
Yes I know all this. It only shows how bugged the military and equipment is once you try to use its features.
But a lot of the bugs is already quite well tested and understood so this can help Toady a lot once he starts fixing them.
Some of them that bother me personally the most:
#1451 Military equipment interferes with civilian equipment (one dwarf can't use the same axe for both woodcutting and axedwarfing, miners and woodcutters can't wear their military uniform when civilian)
#4932 Dwarves try to equip armor in order of its production instead of in order specified by uniform (this means they end up with cloaks instead of with breastplate)
#5485 Assigning "specific weapon / armor" doesn't show which items are already assigned
#4530 Marksdwarves won't train with training bolts unless combat bolts all used up