1. Knees to downed opponents. Sloppy takedowns could be punished, ground game becomes more exciting.
2. No weight cutting. Solutions are complicated, but possible. We'd get better fights and fighters would be able to fight more often and step in on short notice.
3. No rounds, or at least a return to same position. No reason people should be saved by the bell, whether from a beating (eg TJ being saved from Cody) or from a submission/gnp. No one deserves to have an opponent arbitrarily pulled off of them. MMA isn't boxing, it should be one continious fight. We'd also get more submissions as they take time to set up.
4. Figure out something about grabbing the cage. Legalize it, change the cage, make it an automatic penalty. Doesn't matter to me, just make it something consistent. Same really goes for eye pokes, low blows. Figure something out and be consistent. Fighters can stop a couple of takedowns by grabbing the cage, get kicked in the balls, and poke their opponent in the eyes and no one gets penalized. No other sports constantly allows blatant cheating w no penalties.
5. Allow headbutts. Makes stand up and ground way more violent and interesting. Very unlikely to happen but seems mild compared to Wandi jumping in the air and stomping people.