i suggest for dublicated epics to turn into events crusaders equips, how so :
the epic upgrades the most poor equip on the bench of the crusader that got the epic and the cost increase from upgrading a common to a rare

1 epic duplicate is enough to get the common equip
2 epic duplicates for an uncommon equip
4 epic duplicates for a rare equip
none for epic

But what they could do is increase the EP you get for higher rarity gear, that's really it.

actually yes getting a dup epic is quite annoying and i really think that this way of upgrading gear won't tackle the game since getting a 4 dup for the same crusader to upgrade just one equip of one of its bench crusader won't happen so fast. i.e upgrading an uncommon equip for frosty the snowman/or little foot would need u to get a whole 4 dup epics for thalia, and a rare for every event crusader would takes a lot of time to do unless u have almost all rares wich is the case for 95% of the veteran players. so this process will actually help the other players more.