Overrated isn't the right word.
Overhyped. If he'd walked in as a former DI champ instead of "WWE headliner" and crushed a few more guys before he got a UFC main event slot he would've been one of the legitimate biggest stars in the sport.
Instead most people couldn't get over the "fake wrestling" background. If MMA was in 2000 where it is now, I think he would've gone straight to MMA and been a long time star/champion. He hated the pro wrestling scene/lifestyle and craved competition.
But, we'll never know.