1vs1 arena, 4vs4 premade custom matches in feast...That should be the solution, is it not enough? Probably 8vs8 will be obsolete once they would do a 4vs4 unranked and not sure if they want that.Though they could do the same like with frontlines then, if its not a 72 match it becomes a 24man match. If not enough for 8vs8 it becomes a 4vs4 unranked.

But if you are really enough players definetly try custom matches, but usually it is hard to find 7 other people interested in learning feast lol.