The problem with the MMA heavyweights whether they're in the UFC or Pride is that they dont knock out people often enough!
That's the sole reason people wanna see heavyweights in the first place for their ability to put that weight behind the punches. Whether it be stand up knock outs or some vicious g'n'p. That's the reason people loved to see Tyson, cause he had 44 KO's in 50 fights. That's why K1 are heavyweights because they deliver a lot of KO's.
When Tim Sylvia stopped knocking people out and started winning by decision the crowd turned their back on him. Fedor got 6 T(ko)'s in his whole career. 5 of them in 2003 or earlier.