It doesnt work like that in the business of the fight game. It does for pro team sports, but a system like the UFC has is put in place so the company and fights are the most sellable and profitable for that organization but also offer the best competitors and fighter moving up. The issue with what you're suggesting wont work because the rankings system is open to interpretation and opinion based but would also clog up the title and creates repetitive fights. What qualifies one win better then another? If a title contender or fighter loses where does he go? What's the basis for who fights who?
This creates even more problems then anything. You have champ, then #1 vs #2, #3 vs #4, #5 vs #6 and so on. Guys win and move up for title shots, right? Not exactly, this will create so many problems. Suppose a fighter gets injured....#1 is out so who does #2 fight?? They gotta take the next highest guy out and change the fights. This would be a nightmare for fighters training for a particular guy. What happens if they cant find a opponent and #2 and #3 or #4 wins, do they move up over #2? Also, with the system would just move way too slow and you would have the same top 10 guys fighting each other, the system now make it easy for new guys to always enter the top 10. You also have to consider that just cause a guy is ranked higher doesnt mean he's better and more deserving of better fights. Right now you can have a guy outside the top 15 come in a knock of a top 5 guy. What your suggesting wont work in the fight game, it doesnt fit the dynamix of the sport.
Its nothing to do with being more of a "sport" The "sport" aspect is the competitive aspect of the game. What you're talking about is the business and promotions side and that wont change in the fight game, its been like that in boxing and mma for decades and the best and most efficient system.
Well the MMA ELO system is a known algorithm. It's objective and predefined once set. It will probably never be perfect for every situation but we can get it pretty close...
Regarding repetitive fights and how to do it I was just thinking of this and I came up with some rules:
1. You always start with the champion in setting fights and then work your way down.
2. If the first ranked contender already fought the other fighter within
1 year then the next fighter is chosen instead.
3. If the first ranked fighter already fought the other fighter twice within
3 years then the next ranked fighter is chosen instead.
4. If the first ranked fighter already fought the other fighter three times within
6 years then the next ranked fighter is chosen instead.
This is would eliminate repetitive matchups save for where they are reasonable. So in this case Meisha Tate is the #1 contender for Ronda Rousey. As long as:
a)Their last fight was over 1 year ago (YES - December 28, 2013)
and
b) Their first fight was over 3 years ago (YES barely - March 3, 2012)
then Rousey vs Tate 3 would be booked. In this case it would. But if she say had this fight again set for Jan 1, 2016 and she lost it then she would not be fighting Ronda again until March 3, 2018 at the earliest if she still is the #1 contender then.
Regarding injuries they already happen. You can't do much about that. At least the next fighter in line should be fairly competitive.... Also these injuries will help other fighters have the chance to possibly move up faster so it's all good.