I was about to ask my guild to use the desired gear functionality to indicate what Karazhan items they actually needed, but I noticed there's a lot of old members with trash. #1 is there a way for an admin to clean up other member's wanted items and
#2 could you add a filter by instance/boss?

I'm guessing no and no?

I can manually delete all the wanted gear for you, if you'd like, but at the moment, I'm afraid there's nothing in the interface for that.

Would it be possible to have this feature added, think it could be very useful, for instance our guild is raiding karazhan and we're swapping out ppl on each boss and if we could have so that you can sort by a mob that is about to be killed and who needs what from that boss then that there would be worth its weight in gold.

I think a tweak the system needs is to be able to recognize the Character's Wanted Gear with Received Items. If player A receives and Item they want on a specific character in a raid and it is imported for and assigned to that character in the Received Items portion of the import then it should automatically remove it from the Wanted Gear list. The difficulty with this is that would need to be some kind of manual association also because people would list the item they want as the Tier piece and not the coin required to get it. In this respect you could also sync wanted to gear with guild bank and armory imports. If a character has equipped or in bag/bank a piece gear in their wanted list you could do a check and remove it.

There's also the issue of people that have alts but all of the DKP is given to their main (a system where DKP is player based, not character based). Currently, in order to properly handle that, you have to say that their main received the item so the DKP is removed from the proper character.