Your team :P
Well of course design is important as Proph said, but The current items in RotMG aren't made for endgame, if you look at Doomed Realms, it does kind of the right step, but the items are kinda way too op imo, But if you look at other RPGs the items you obtain in the endgame will destroy the begining land, which the realm is kind of, I mean this game needs something new, the formula will break someday