This isn't based on much though... he has some big wins in JDS, Brock and Bigfoot (maybe Rothwell too but I don't think Rothwell was as good yet back then, it was a long time ago) but he isn't a GSP or Anderson figure who ran through a division. He hasn't beaten Werdum, Stipe, Overeem, or Barnett and in fact lost to Werdum so it's hard to extrapolate him being close to unbeatable "when healthy".
He has wins over 3 guys that were considered great wins at the time, that's more like a Pettis resume than a long term divisional dominator.