User blog comment:FairyRaven/Fairy Tail Chapter 360:The White Inheritance, Review and Commentary/@comment-4643135-20131117042608/@comment-24066070-20131117090817

I understand why people would want other guilds to join in, but there are some downsides to such a scenario as well. Fights may be too rushed or even happen completely off-screen if "too many" people show up. Furthermore all these mages have recently fought in the GMG, so likely they won't join in until the final battle or even the next Arc in order to give them time to train and show some new stuff when they make their appearance.

I think the story is currently in the stage where FT get their asses handed to them. They will suffer damage while trying to protect the former MC members, retreat in order to heal and come up with a strategy, then they will have the second round where they beat the bad guys. Whether other guilds join the second round remains to be seen.