Dana White once criticized boxing because it didn't have their mega fight in Floyd Mayweather vs. Manny Pacquiao. So far in the UFC we haven't had any of those super fights that gets everyone so pumped up for. We got really close to a Jose Aldo vs. Anthony Pettis fight but that really isn't considered a super fight and was scrapped due to injury.
It was reported that Dana White hopes to seal a deal with Gina Carano really soon. If Carano is signed and they match her up against Rousey, this could potentially be the biggest fight the UFC can make right now. I am taking Cyborg out of the equation only because the UFC is hesitant on signing Cyborg because of drug issues and will we see if she can make 135 comfortably. If we go division by division, let's see if there is a fight bigger than Rousey vs. Carano.
By process of elimination, you could eliminate the flyweight, bantamweight, and featherweight from any fight you could make that would be bigger than Rousey-Carano. In the lightweight division, the fight we are going to get between Anthony Pettis and Gilbert Melendez is the biggest fight that you could make but it doesn't stack up to Rousey-Carano.
With the absence of GSP and Anderson Silva, the Welterweight and Middleweight division has lost that star power. for both champions matching them up with any opponent wont have the star power necessary to be considered as the biggest fight the UFC can make.
The one exception is a fight between two non champions in Anderson Silva and Nick Diaz. When this fight was rumored to happen a lot of MMA fans got really excited about this. mmafighting's own Luke Thomas was dreaming of this fight to happen, even saying if this fight happens there is a God.
In the last two divisions the primary guys you would think of is light heavyweight champion Jon Jones and Heavyweight champion Cain Velasquez. The biggest fights for Jon Jones is the rematch with Alexander Gustafsson, and a fight against Daniel Cormier.
For Cain Velasquez, because the heavyweight division is so thin there aren't that many guys at the top of the rankings that Cain hasn't already defeated. Jon Jones said he will probably move to heavyweight before his career is over so that could be some good news for Cain. The biggest fight Cain can have is a fight that will probably never happen and that is a fight with his training partner and friend Daniel Cormier.
You may agree with most of what I just wrote or you could totally disagree with everything I just wrote. Their is no denying that Ronda Rousey vs. Gina Carano would be the major event the UFC has been waiting for in a long time.