I honestly think the entire WG roster is lame as fuck.
Some Gorosei LOOK cool, but that's it. they were all there in Egghead and they still failed hard at their job.
Imu is a lame reveal, lame villain and i have 0 investment in it.
I like this arc, i enjoy Sommers' character, i enjoyed Gunko's usage of her ability. But the issue is that Oda's "summoners" and "manipulators" type of enemies are all pretty weak and are mere gimmicks.
The ceiling this arc, imo, would be Zoro vs DR Sanji and Luffy vs DR Loki.
Anything aside from 2 matchups is definitely underwhelming and is mere ACoC training tool.
I'm looking forward more for the post elbaph stuff.