Bias aside, Mcgregor recently acquired two belts in two stacked divisions. He's talking about possibly fighting for the welterweight belt, but if he does that next, the featherweight title should be abandoned. It's been held up for too long. If he wants to get the welterweight title, and hold 3 titles, I think the right path is this:
featherweight defense->lightweight defense->welterweight try
Even if he defends lightweight next, he should drop the featherweight belt. He's already achieved the 2 belts simultaneously, and losing the featherweight title would hardly diminish his achievements.
If he defends featherweight, Aldo obviously deserves the next shot. If Holloway beats Pettis, he should be guaranteed the winner of Conor/Aldo. (If Pettis wins, he should either get the title shot, or fight Frankie for the contender spot. Or, if Pettis wins, Frankie gets the winner of Aldo/Conor with Pettis guaranteed the next title shot.)
When Conor defends lightweight next, I don't see any argument against either Khabib or Ferguson getting the fight. If he defends against Khabib, Ferguson should be guaranteed next shot. And if he defends against Ferguson, Khabib should guaranteed the next shot. Both of those guys have done more than enough to get title fights. Playing more contender elimination would be unfortunate.
Since Nate is sitting at the number 6 spot, why not Nate vs. Alvarez? Alvarez is coming fresh off of the Champion position, and deserves competitive match-making. Sherdog suggests him fighting Will Brooks next, but I find that ridiculous, as Brooks is at 14 and did not go through the murderer's row that Alvarez went through. Besides, Nate and Alvarez had unsettled beef earlier, and were both recently in the limelight, so a fight between them would be legitimate and anticipated.
In short, the next fights, in order, should be these:
-Conor vs. Aldo
-Conor vs Khabib/Ferguson (Even if Conor loses to Aldo, this should still happen as he'll still have the lightweight title)
And only if Conor defends his lightweight title:
-Conor vs. Welterweight Champion
If he gets all 3, he should defend featherweight->lightweight->welterweight...repeat and stay proven as the champion in the divisions, or else drop the belt(s).
Also:
Nate vs. Eddie