I just finished "get 250 epic girl cards." I then got through one more event quest (get five chests), but now I am faced with "get 250 rare event girl cards." I've literally only gotten through two event quests in the last few days (both today) while playing quite a bit. I was lucky enough in "get 250 epic girl cards" to get one of those shiny chests from the tower with 70 epic girl cards in it, but now I am totally dependent on defeating the boss 13 times. This is fine unto itself, but the timer is an hour, so I have to spend 12 hours, mostly waiting for the boss to load. I think the wait time for the boss should be cut down substantially if not removed all together.
This kind of quest makes the game play monotonous. All I do now is, beat the boss, fill all four chest slots, beat the boss again (which I am waiting to do right now), and leave the game for an hour to wait for the boss to regenerate, and repeat. I have to do this in the next few days, and still, there will be 3 more event quests to accomplish. At this pace, I probably will never get the chance to unlock the legendary girl. I haven't yet, and this is the third quest I've done, and these types of quests, where I have to fight a boss every hour, is why.
I suggest replacing this quest. How about something like, complete 5-10 normal quests? That would be doable in a reasonable amount of time (like an hour or so), and one would not be limited by a timer, which really sucks when you just want to play a game.