Firstly, you can't forget about the money. Hopefully, when the game progresses a bit more, fighters will need money to survive (just like in real life). Also there will be more businesses for fighters to spend their money on.
Secondly, regarding the fact we are only allowed 2 sponsorship deals per fighter. Again...hopefully when the game developes and we see more types of business it would be a good idea to be restrict it to say 1 deal from each type of company.
Now I'm no expert! But I know for a fact that some pro fighters do get sponsored from the gym's they train at, by getting free training.
Also while I'm on a roll, , I think another good idea would be is when a fighter eventually retires it would be a good idea to have the option for them to become a coach (either train them or whatever). I know this is a while away but just thought I'd mention it before I forget about it lol.
Now before you start on at me about how complicated these ideas are to sort....DON'T! Because I won't have a clue about the technical stuf that you will tell me. lol