Events in this game are never-ending. As soon as an event ends, another one takes over immediately afterwards. They are poorly designed, recycled over the years (ToM and Yeti dungeon being prime examples) and unrewarding, bust most importantly they feel like doing chores instead of being fun. Double event currency makes it even worse.
My point: You should do like 4 events a year, and make them super rewarding. Not only will this bring back a lot more players because they'll be excited to play said events, but that's what an event is supposed to be in the first place: scarce, fun, and gratifying. Like provide tons of materials as we need, for instance, thousands of moonstone crystals for pretty much everything. And elusive items and outfits. Not the usual recycled garbage we're currently getting.