It's probable we'll see VGC'15 on steroids (hey I guess I'm relevant again lul) so consider that, given the formula Gamefreak ALWAYS pulls out since gen 5 we'll see the weaker legendaries combined with the Tapus, which is pretty much the current BSD metagame atm.
Now, while it is unhealthy to speculate this early, I'm pretty afraid of what Alola's tutors could give us. There are plenty of Alolan Pokemon whose moveset is pretty lackluster and that's the only thing holding them back (like Silvally), so thoughts like Tapu Fini or Celesteela getting Tailwind and, what is even worse, High Horsepower becoming a move tutor scare me a lot of what this metagame could become.
Now, while it is unhealthy to speculate this early, I'm pretty afraid of what Alola's tutors could give us. There are plenty of Alolan Pokemon whose moveset is pretty lackluster and that's the only thing holding them back (like Silvally), so thoughts like Tapu Fini or Celesteela getting Tailwind and, what is even worse, High Horsepower becoming a move tutor scare me a lot of what this metagame could become.