Something to note is that when Sugar was knocked unconscious, her contracts stopped working. If the same is true of Imu, then there is a way to reverse people being transformed.
We've already seen Rock return to normal after being defeated by Garp and Roger. Detransformation isn't a problem as long as his opponent is strong enough. The issue here is Imu's power development, which seems to be only repeating.
Besides, the hype so far has only been focused on WG's opponents: Loki, Shank, and SHP. WG appears to be nerfed, especially after it was revealed that none of the God Knights can play CoC.
This wouldn't be a problem if we were nearing the end of One Piece, but considering the story still seems to have a long way to go, WG already seems weak.
BB might be a gamechanger, but it's still not the main plot anymore. Loki's powers completely ruin power-scaling and make the story a mess.