Right now u get a lot of group coins for participating, which after a few wars, u should have enough group coins to get 1 character from group shop,not to mention new characters are gonna get added to the shops later on. This isn't the best way to make participants happy, but it's a start, instead of getting seals, u get group coins,which guarantee you a 3* of u're choice (from the limited options we currently have). Tbh as well, assuming u get the legendary pack every time it'll just give u zabuza, as for the runes u can get them from the shop, so rly it isn't that bad, just think of the gifts as a bonus.