He was a freakshow who was fed smaller and weaker opponents. He tapped to Reem's strikes didn't even get KO'd. That Cain loopsy cartwheel just showed how silly he was.
If he were a legit HW he wouldn't have ran back to Wrestling.
All the best HWs ever were smaller HWs (Fedor, Randy, Nog, JDS, Cain, Werdum). Being big like Brock has historically almost never been an advantage at HW. No matter what anyone says beating Randy, Mir and Carwin makes you a legit HW. He was not the best HW in the world but he was legit