I've always been an Adam Cole fan but he hasn't looked nearly as good in AEW as he did NXT and ROH and shouldn't be an AEW World CHampion. To me, his AEW tenure has reminded me of the pro athletes that have a career year before they were set to become a free agent then they proceed to shyt the bed the following year after getting their fat contract in the offseason.
Multiple reasons why I believe he hasn't been as good.
He looks like he hasn't cared at all about keeping his body as toned as it was in NXT and ROH. He never has and never will be a big muscular guy, but he's basically a beer gut away from having full-fledged dad bod.
The talent in AEW is considerably more talented, more athletic, taller, and more built than it was in NXT and ROH. The size disparities tended to be much less in NXT and ROH. I don't necessarily believe that you have to be big to come off as a credible champ, but you can't be short, lack muscle mass, and be unathletic in AEW and be taken seriously by anyone other than Adam Cole fans. In the big leagues, if you lack size height you need to make up for it in muscle mass and/or athleticism like Bryan Danielson, Young Bucks, FTR, Jericho, Adam Page, Jay Lethal, Kenny Omega, Malakai Black, Miro, MJF, Pac, Penta, Fenix, and Starks. All those guys billed at the same height or shorter than Adam Cole, but they all make Adam Cole look small, and other than the Young Bucks and FTR, they would all be reasonably believable as the AEW champion in my eyes.
I think the biggest is that he just hasn't been booked as well nor performed as well. Part of that goes back to the things above, In general though, it's harder to book less believable talent. His promos have been of much less caliber than they were prior to AEW. And while he has had some good matches, though sparingly few like one against Adam Page, they just haven't been up to the level he was consistently putting out in ROH and NXT. Everything he has done in-ring in AEW pales in comparison to at least a dozen, maybe two dozen, matches he had in NXT.