First I'm going to start by saying UFC currently has 392 fighters under contract. The UFC plans to run 32 shows next year the average will be 12 bouts per card so that obviously means 24 fighters per card , that math would be 768 but divide that by 3 because most fighters fight 3 a year and you have 256. So mathematically speaking you would need 256 fighter to fill all those spots of course your going to have injury's so you need a few extra fighters as well. If you take the 9 divisions and multiply that by 30 you have 270 fighters , which means the UFC has 122 more fighters than they need in theory. If they were to cut the roster size down that also fixes the problem of people complaining about watered down cards because outside of 30 per division do the rest really mean anything to the UFC anyway? Also instead of having 11-13 fights per card we could go back to 8 or 9 fights per event and kill the facebook / youtube portion of the event. If they were to cut back to 9 fights per card that would be 192 fighters if each fought 3 times a year. Which in turn means UFC could keep just the top 25 in each division and it would still give them an extra 3 fighters for each weight class.