While I agree that the event format is getting a little tired, I'm not sure what else the devs can do.
Our cities produce, upgrade, expand, and advance, so that is pretty much the pool of quests they pull from.
how about a quest that asks you to find a random chest 'thingie' in a neighbours city. they allready do chest and mana essence etc randomly in the map, that could be used for a quest.
How about they add a new production in the magic academy, that uses limited time goods (maybe from random drop around the map) and that you need to create that for the event.
There is really much more you can add for an event then using only the features that are allready there.
But honestly, i dont think any new quests will come before the quest overhaul is complete. I imagine they are redoing the quest overhaul mainly so they can add new kinds of quests.