I would reintroduce tournaments as per the original UFC I, II and III. These wouldn't be "title" matches for belts, but one-off tournament bragging rights. I see fighters like Frank Trigg, Chris Leben, etc. lose a couple fights in a row... and head towards no-man's land for their future... diminished in importance, released from UFC, whatever, etc.
I'd run a "One Night Fight" tournament every two weeks, each tournament involving one weight class, with 16 fighters entered:
— Round 1: 8 fights
— Round 2: 4 fights
— Round 3: 2 fights
— Round 4: 1 fight (Finals)
Win four fights, and you win the tourney. Every 10 weeks, the five weight classes have been gone through once. Every fighter, no matter what their standing/rank, would have a chance every few months to enter an all night tourney. Pay each fighter an equal flat fee, then a bonus for each win. The guy who wins the tourney makes the most money.
Make it a Saturday night 8 pm - midnight thing (15 fights total), and put it on regular TV. This would give everyone a look at many fighters other than the belt holders. It would create awareness of the PPV title stuff, give a place for losing fighters to redeem themselves, and put victory by attrition back into the sport. And give a place for that big sponsor to advertise.
And if that worked out, I'd look at having European versions, North American, South American, Asian.... then have twice a year the champions of each zone go against each other. Make an Olympics of the whole thing.