Aikido for all.
There are for sure moves that would be excellent to use in a MMA fight. (Maybe MMA will be an olympic sport - that would be entertaining for sure.)
Again, it seems that people get caught up in saying that 'one way' is the only way. (Even the BJJ people get caught up in this illusion)
One way is suitable for whatever circumstance it was created for, and even then it needs adaptation and fluidity. (Some could say this philosophy is what is at the heart of 'Aikido')
Again, Aikido can be to anyone whatever it is they want it to be.
Tai Chi like or used in competition...or both.
(caveat: twisting joints in sports can make it the last time you compete in said sport...but then I suppose getting your brain beaten out in MMA and boxing isnt much different.)
Aikido, as it generally is learned, is quite effective.
When it becomes less effective...or rather needs adaptation, is when you have 2 people in a ring with the mind set of going at each other.
So if someone is in a bar and getting rowdy, someone could get a move rather easily - also in situations where it is push and shove and both sides are not really wanting to start hitting right away.
Again, different times, places, means that different techniques could be used and applied.
Aikido, on a darker note, would be an idea 'bully' sport - until someone gets tired of the person pushing them around and punches them in the face.
This is where emphasis in Aikido training would need to be about attitude - and not using it as a means to bully others.