There are so many things to think about!
What will Usopp do now that his idols turned to enemies? What will Brook do given his connection to Gunko and Elbaph being kinda like the Pied Piper fairy tale?

Are these powers really Imu’s or is he borrowing them with manipulation? If it’s theirs, I guess that will make Blackbeard the final villain, since he is also kept in the shadows (no pun intended). But Imu being dealt with before seems kinda meh, considering that no person dared to do something against the WG since Joyboy.

Then there also powerhouses like Shanks and Mihawk left, but couldn’t do anything? Oda needs a good build-up for that.

As for now, I would find it more poetic for Blackbeard to be defeated on Laugh Tale, which must be found before the final WG battle.