Dana has $$'s in his eyes. He's always said nobody can have two titles. The last really serious time this was being talked about was way back when BJ Penn was the big champ and undefeatable - but Dana wouldn't do it then. This fight with RDA has the ability to make Connor absolutely the biggest star the sport has seen (if he is already it) but like Gator said, if he gets steamrolled by RDA it will hurt for the long term.
If it is a close decision then not so much, but if RDA comes out there and power doubles Connor into the floor by the cage and unloads on him or if he just bullies him against the cage then it will be a big blow do the Connor mystique. Right now he is coming off his Chad win with the live intro and then stopping Aldo. I really think UFC might be pushing to far with him. Connor has two big wins - Chad and Aldo. Chad had 10 days notice, and Aldo was coming back from 18 months out and got flash ko'd by the first punch.
Connor has done amazing things, but he definitely had an easier road, Not completely by the UFC doing. Aldo got injured so they had to fill in quick with Chad, and then Aldo being out for that long. UFC favoritism is a factor now though. Rousey and Cain both get instant rematches after they were straight up dominated, but Aldo gets a flash ko'd and he is back of the line.
As for Holly v Miesha - I like Miesha. In terms of girl fighters I believe she is the most complete female fighter. She has good wrestling, good jiu-jitsu, and good striking. Holly is definitely the favorite, but I think Miesha is a live underdog. She brings much better striking than Ronda and much better wrestling. Holly did not have to worry about any type of single legs, double legs, ankle picks, or any thing else from Ronda. The threat of Miesha's wrestling may be enough to make Holly uncomfortable and put her in a bad position. What happens if Holly is on the mat with Miesha on top?
In terms of marketability - UFC absolutely does not want Miesha to win. She is attractive and good on the mic, but she does not have a sliver of the Ronda hyper behind her. Now that Holly is undefeated and dethroned Ronda, they are putting their eggs in her basket (at least until Her Holiness RR returns to us). People who know nothing about UFC know all about Holly vs Ronda. It was on a bunch of the year in reviews on New Year's Eve and even on the New Year's Eve Google commercial had Holly entering the cage. If Ronda is out (or maybe done), Holly is the one to continue the banner. She can be the new unstoppable female fighter that everyone/everything gets behind. Joe will be calling her the greatest athlete of all time next week.
Holly winning though will just help cement how good she is and make the Ronda rematch even bigger money. If Miesha wins - it is all well in good, but it just seems anti-climatic. Lost to Zigano, lost to Ronda twice (once in the first round) and then lost to Kaufman back in Strikeforce. Miesha has nothing to really market her except decent skills and is attractive. There is no "it". For Jon Jones it is steam rolling everyone since Shogun, GSP was just how perfect he was in not losing a single round, Fedor was the unstoppable Russian machine, Connor is Connor, Ronda has a highlight reel of armbars and quick wins, Anderson Silva had his matrix style KOs. If Miesha wins it is is like if Ryan Bader beats Rumble and then finally gets his title shot and beats Cormier. 100% deserving of the title, but a much harder sell to the casual fans.
Casual fans are what make the big money. The same dedicated fans will always watch to see who is most deserving, but it is the casuals he make the difference between a 300,000 PPV featuring Mighty Mouse or 1.1 million PPV with Connor or Ronda. It is why UFC does what they do. Rankings only count for so much.