Khabib, unironically, had the best title fight and title defense. Al Iaquinta was proven already. He had a five fight winning-streak when the Lightweight Division was in its prime prior to facing Khabib. Al Iaquinta had beaten Kevin Lee (before this win-streak), Joe Lauzon, Masvidal, and a Diego Sanchez who was coming off a win over 22-4 Marcin Held (who beat Pitbull). Iaquinta was 8-2 in the UFC LW division. He then went up to 9-3 after losing to Khabib because he beat the crap out of Kevin Lee again. All that talk about him being a real-estate agent is just libel.
McGregor was also the last linear Lightweight champion, who hadn't lose his title at that point, he had only relinquished it. A title he won relatively easily (yeah, he got lucky with getting Eddie Alvarez as his opponent, but it was still a dominant win). He also easily defeated everyone at Featherweight. The Nate Diaz fights showed he wasn't elite, but he was no pushover either.
DC against an old Stipe whom he eyepoked, and who was coming off a war against Ngannou, and then chubby Lewis? Jones against no-grappling Gane, who only fought for the title because the HW was in a state of decadence, and then an even older Stipe than the one DC faced?
