A few years ago, most people were in denial and couldn't accept that Shanksu and Mihawk had surpassed the likes of Roger etc but now they are ok with it.
I'm not crazy enough to say they're stronger than Imu, but if we find out that Shanks beat Loki fairly, anything is possible...
It is basically old gen wank. Many people think Sengoku > any current Admiral.
Remember Harald and Xebec clash at holy land and didn't result mass destruction unlike Fujitoria and Greenbull. Kuzan has Garp physical strength. Pre timeskip Teach is > Prime Xebec yet run away from Alainu like he is Grim Reaper.
Shanks get wank which many people ignore it. I say Shanks > Joy Boy/Imu easily. They can me crazy. Same apply to current admirals, Mihawk or even Dragon if he has plan somehow. Kizaru fed luffy that same luffy beat kaido.
It is mid generation is actually strongest not weakest.
Big mom or Kaido doesn't have feat like causal Kizaru laser kick destory tree at Sabaody which it lump tree as island.