They need more big rivalries. Couture/Liddell, Liddell/Ortiz, Ortiz/Shamrock, GSP/Hughes, GSP/Penn, Hughes/Penn. We had multiple rivalires between many of the same guys who just happened to be some of the biggest stars in MMA at the time. We don't really have that now. We've got little tastes of it, but nothing like it used to be.
They need more big rematches. Look how many buys Silva/Sonnen II did. It's because Chael almost beat the unbeatable Silva and people wanted to know if Silva got lucky pulling the sub out of his ass, or if he really was the better fighter. Same with Silva/Weidman II. Weidman caught him clowning and people wanted to see if he got lucky or if he could beat him again. Jones/Gustafsson didn't do great. But a lot of people wrote off Gustafsson from the time the fight was announced. But he pushed Jones to the brink, and in the immediate aftermath, many people thought he won the fight. I would bet you anything that the rematch will pull in big numbers. A GSP/Hendricks rematch would have probably done big numbers. When champions who are perceived as unbeatable lose or almost lose, the rematch is usually big business. Obviously, you can't plan for this to happen. It's usually by surprise, but given the close calls the champs all had last year, this year had big potential for big rematches. GSP took a hiatus/semi-retirement and Silva is on the shelf. But they could still capitalize on those fights in the future if/when they come back.
They need more big superstars. We all know what is going on. Rather than creating superstars, the UFC relies on the brand itself to be the catalyst for sales. Obviously, some fighters move the needle more than others, though. Lesnar was huge for the sport. It will be tough to get somebody who can be that kind of a draw again. They need to find their Mayweather or their next generation Lesnar. Guys who are bigger than the sport. Also, because the sport is so new, the guys who were there at the beginning all faded out around the same time, making way for the new stars of the sport. Guys like Couture, Liddell, Hughes, Penn, Franklin, hell, even Sylvia and Arlovski, they came out of the ashes of the dark age and helped popularize the sport in the wake of the TUF boom. they all started to fade out of relevance around the same time. On tope of that, most of the guys from TUF 1 are retired. So people who became fans around that time are trying to fill the void of their favorite fighters no longer being active. The Pride fighters are all also mostly out of the picture.
The UFC had the perfect storm. TUF, the first wave of true superstars, Pride fighters signing with the UFC, and Brock Lesnar all happened in just a few years time and the UFC was huge. Once that all died out/faded away, it was followed up newer, smaller weight classes and WMMA that split the fan base, increased the roster creating "watered down" cards, global expansion and the signing of many unknown fighters in effort to start farming their own talent, which saturated the prodect even more.
But what is crazy is that fighters today are better than they were back then...and there is more of them. Today's champions are better than yesterday's champions. The challengers/contenders are better than back then. Many of them would probably be champions back then. The gatekeepers and mid tier guys are better. The up and comers and prospects are better. But you don't notice it because there is so many of them. Before it was several big fish in a small pond. Now it's even bigger fish, but the pond is so big, you don't notice as much. They don't stand out like they used to. That and '05 through '10 was just such a tough act to follow.