Good day sir,
I would like to suggest that the current time-limited ninja recruitment will be permanent :) this will work well also with daily missions :)
It will make players very active and/or spend moneys on keys, also I would suggest that the items inside will be different every week (just like the black market but longer) so it would be interesting :)
2 rare fragments that is not (yet) obtainable in instances (is the main thing in the event)
here are the other item suggestions
coins (300k)