Here's a question: why is there no trapping (as in the majority of aikido waza) in MMA? Or perhaps I should ask, has anyone managed to pull off locks against a good, resisting opponent?
Is aikido just made up of low-percentage techniques? Or are there just not enough skilled aikido people trying MMA?
Trapping is very hard to do. I can teach someone to block and punch in a fairly short time. I've been training aikido on and off for years and I can't even come close to doing most of it in a sparing match. There are many reasons for this. First, most people will not commit to their strikes taking them offbalance like in the dojo, instead they throw combos with good balance, and they always retract their firsts to a good guard. Attempting to perform an aikidoish technique is going to require perfection, anything else and you are going to eat the next blow in that combo. A good cover and punch type striker is going to have much more success then someone trying to do trapping for the first few years of their training. Another problem I've noticed is that the wrist when taped and gloved is very hard to manipulate. I catch wrist locks a lot in bjj now. I spent a few weeks learning how to get them with some degree of success (about 70% of the time I go for them I get them). I use them to setup armbars, and sometimes to tap out my partner. However, I have not gotten a single wrist lock to work in MMA, even against people I catch with wrist locks in bjj constantly. Finally, due to the vunurablity when you do fail, it is better to use consistant high percentage attacks that do not leave you as bad off when they fail. For example, a good boxers guard may allow a few shots though, but it keeps the chin down and protected most of the time. Reaching from that position however exposes the head, and if you screw up, you are at a much higher risk of getting caught by a shot in the chin.
Judo is a good example. If your opponent is off balance, you are in a world of trouble in MMA. This is why wrestling take downs have become more dominate, the rules allow less risk when you fail. You know the guy can not punch you in the back of the head, and he can't knee your face with 3 points down. So you can shoot and if you screw up you are ok. Try a hip or shoulder throw and screw up, you are getting lifted slammed and pounded. Now look at most aikido throws. You are even worse off if those fail.
Of course there are always masters who can make anything work. What you are seeing is a constant change in MMA. I don't think you will see the skillsets solidify for another 25-35 years. However the level of skill will always be improving. I watch the old pride and UFC vids today and I see a crude level of skill. Then I watch good MMA guys today and I see refined skill, but still differences between camps and ideas. In another 25 years it will be like boxing, only 1 or 2 really good ways to do it. Then we can wash, rinse and repeat with the next thing.