Looks like we have a hint at the next patch.

Forgive me, but that makes no sense.
If you only focus on SAO, then the only people drawn to Maple for this update will be those who are already SAO fans. What's SAO's gain from that?
On the other hand, if you advertise other content too, you get people to join Maple, or return to it, who just want the Blaze Wizard, or whatever else is in store. And then they will see the SAO events in the game, and maybe become drawn to the show.

This is a stretch, but perhaps there are contractual issues involved? Something like "you can use SAO themed material but only if you strongly focus on SAO during the update".