This suggestion has been made before, but I thought it would be nice to have it up there by itself. The maximum number of duplicate items that a 3 member party needs is a fixed amount. For example, 3 of each shield, 9 of each weapon, 6 of each divine weapon, etc. Any excess items beyond that are superfluous if you aren't a collector. I would be very pleased if the developers could implement a button to let us sell off excess items with one click. Currently, I squint at shield and armor icons to figure out if I have 3 or 4 of each. Sometimes I overclick and end up selling an extra item, which means that my OCD tendencies scream out loudly and I cannot sleep. j/k It would also help my RSI when liquidating my stock of treasures after a long campaign run - a full campaign run can net around 100 items, which means a lot of repetitive wrist-hurting clicks. There is also a noticeable slowdown effect when loading many items - I think turinturamba was the first to bring this up, though many others have commented on this. For this reason, having the ability to sell off excess items would be really good for reducing load times when kitting out parties or swapping out equipment between adventures. There may be players who prefer not to sell off certain special items, like the Demon's Snuffbox that we just received. For that, I would suggest having some kind of way to mark items as unsaleable. Perhaps, have a chest in the player's keep to display these items? Sort of like a trophy showcase. Help my RSI!
Also suggested here on October 21 by piotras and on October 9 by me. To quote me from the October 21 thread: I'd also guess it's been asked for every few weeks since the beginning of Card Hunter.
I wouldn't mind if this button only affected items. I treat my treasure differently and the collection is small enough that I can manually sell the extras.