I was going to post this in the comments to one of the other articles but I was afraid it would get lost in the shuffle and I think it's an important point that needs to be heard. I haven't heard this anywhere else and I think there is one very important reason why UFC fighter pay cannot be compared to that of any other sport.
The UFC derives the vast majority of their revenue from Pay-Per-View buys. Obviously we have no idea exactly what the percentage is but I think it's a safe guess that over half of their revenue is from PPV. And the reason they make so many millions from PPV is because of the stars who sell fights- Brock Lesnar, Georges St. Pierre, Chuck Liddell, BJ Penn. The casual fans (which makes up most of the PPV buying fanbase) tune in to see these big names. The guys like Gray Maynard, Jon Fitch, and Gabriel Gonzaga are completely interchangable parts, no matter the breadth of their skills. In other words, these guys mean very little to the overall bottom line of Zuffa LLC.
The reason the big 4 sports leagues pay such a high percentage of their revenue to the players is because even the marginal guys (the 4th starters in MLB, the sixth man in the NBA, the backup left tackle in the NFL) on the teams can make a big contribution to the success of their team and therefore they are worth much more to their respective teams. The more success a team has the more money they make (I know this is a simplistic view but for the most part this is the case) so they have a reason to stack their roster from top to bottom with the very best players possible. This is not necessarily true in MMA, or specifically, the UFC. While it would be nice to have the top 25 guys in each weight class, realistically as long as they have the top 2 or 3 then that is all that matters. There is no reason for the UFC to pay millions (or even mid to high six figures) to a guy like Fabricio Werdum or Dan Henderson if they don't provide a reasonable threat to the #1 fighter in their class, there is no monetary gain to keeping those guys around, in fact it would only cost the UFC money in the long run.
I don't want to come off as being anti-fighter, I agree that the guys at the bottom should be getting more but at the same time I don't necessarily think they deserve 50-60% of total revenue like the athletes in other sports get. The UFC and other major sports leagues operate on very different playing fields (both literally and figuritively) so I think comparing the two is an exercise in futility. It's no more fair to compare the UFC to Major League Baseball than it would be to compare the UFC to Google or McDonald's.