How many times did he grab hold of Melendez and use that "killer instinct" None because its all he has and everyone knows it. Instead he just kept scooting around on his butt looking like a small child throwing a temper tantrum. Even when Melenzez recklessly dove into his guard Aoki failed to really mount any kind of offense. Face it Aoki is a great BJJ guy without any ability to get the fight down or strike to set up a TD. Aoki fighting Gilbert Melendez looked like Thales Leites trying to fight Anderson Silva if Leites somehow could have been even more terrified of Silva.
The answer to your question is easy Toxic. It's because Gilbert Melendez had an excellent game plan and is obviously better than Aoki. Which is why he's ranked higher.
Okay I see your logic here. So basically B.J. Penn has absolutly no BJJ what so ever because he was able to do absolutly nothing with Frankie Edgar on the ground.
As a matter of fact he has zero striking as well since he was getting tooled on his feet, because if he was world class in those areas he would have destroyed Frankie Edgar.
Also he has no TDD because he was getting slammed on his ass time after time..
I got you. I think Joe Stevenson could probably beat Penn too.... but wait...