It would be nice if the monthly changed based on what you already have. For instance, having Basic and Medium anything is totally useless to end game players that no longer need them. (Basic's in general should be removed from any event. You finish those so easily.) Having all Pains 5* makes their frags useless when we have no clue when breakthroughs for them would come out. At the current rate it'll be years since we haven't even gotten all of the basic ninjas yet. Not to mention they are easy enough to get through various other places like the shops, survival, sweeps and arena rewards.

That only leaves you with the stronger ninja if you need it, the seal and summon scrolls and purify. :/