I think people took imu aa God tier or top 1 way too overexaggated.
Old Gaban coc Blast can piece Omen shield Imu.
But can't piece coc barrier from HK Harald.
I think we are underestimate Harald a lot. Imu calling him monster for reason not Rock Xebec. Whatever you beleive Loki vs Harald, it was hybrid Zoan Loki overpowered him, put sense on him, that is dominating the fight.
Imu won't look physical monster on his form, he can be hurt but his body is way tougher than Kaido so making him bleed mean you can make kaido scream in extreme pain.
None of Luffy, Gaban, Loki, Sanji, Zoro look done,
I beleive Shanks or Dragon will come to show off their moveset. But I think.shanks has highest chance due we getting to know Shanks past life at Elbaf arc