If the trend continues and we will get edo han, utakata and fuu "soon", I wonder if thats the right move. Getting Fuu, who is Ay-meta counter ninja before Ay-meta even begins seems a bit odd. But then again we got Kushina before people could play with naruto-roshi-bee lineups, so propably anything can happen. Still I dont think that would be a good idea, I'd rather have those edo jinchuurikis available in treasures as well, not event only. There are a lot (and a lot, lot more to come) event only ninjas, and I believe treasures would be more healthy way to introduce at least some of the ninjas, no matter if the treasure is permament or not.