He's not as over as he was when he was his most over. That's what "cooled off" means. I wouldn't put him ahead of Reigns if you compare the crowd in the main event of Summerslam to the crowd during his match with Miz, which I loved, but it's just true. Sure, anything after WM30 could be a step down, but I'm thinking the night he came back when KO and SZ laid him out. I do think it would have been possible to sustain that.
I'm not sure the crowd reaction for Styles is much different. They feel about roughly the same, which is still a good spot if you can get it, but not where he was at his height.