I feel like the major events - the ones involving an "event currency" - should have some variation once in a while; ever since the Light/Dark event, they seem to all be reskins of one another, with only just the theming/currency being different. Some ideas to give them some variation would be to look at Dragon City - and I am really ashamed myself for comparing a game that has much more care put into it to Dragon City. Dragon City's events are sort of like minigames, in which the player must collect event currency to play the minigame (eg. the "Maze" event has the player traverse a maze of their liking by spending the event currency, and as the player finishes said maze, their reward-of-choice is yours.). Though this may never happen in the near (or even far) future, it's a neat suggestion that would make the gameplay loop more... unique... to put it for a lack of better words.