Pound for pound Khabib is the best fighter in MMA. I don't think anyone at that weight has any chance to even win a round against him. No fighter in the UFC has ever been that dominant except for Jon Jones and we know Jon Jones is currently surround by suspicion and scandal.

As a fighter what makes Khabib most scary is not his athleticism. There are other fighters who have better footwork, who are faster, who are stronger, but what makes Khabib special is his fighting IQ. He reminds me a bit of a Mayweather or a Jon Jones where even if someone is more athletically gifted then they simply out think their opponent. Jon Jones did this against Cormier in their last fight. Khabib did this against Conor.

Conor had to fight Khabib's style of fighting because Conor had more to worry about from Khabib in terms of threats of the takedown. This allowed Khabib to gain an upper hand in striking which was really Conor's best chance. Khabib also has under rated striking ability and can box quite well so Conor wouldn't have had an easy fight even if it stayed standing for the whole fight.

They should rematch and I think Conor has a better chance the second time around but if Khabib can get any fighter to the ground it's pretty much a done deal. The only fighter who I think could out grapple Khabib in MMA is Ben Askren.