My suggestion is to make an undaunted key merchant. You can let this idea run while!
1 merch for all findable sets in dungeons you can even change the traits they have every week.
1 merch for monster helms and shoulders. Like the one in cyrodiil every week.
Both these NPCs can always be there and sell these sets for a certain number of UNDAUNTED KEYS. That way there's no gambling all your keys away.
Armor and weapons can be improved with 100% rate the more resins you use so why can't this idea work?