There have been enough fights out there that if it was effective that chances are we would have seen it by now and used commonly.
The question and entertaining this any further really becomes an intellectual exercise of the useless type. Crudely referred to as mental masturbation. Crude, but I think it captures the essence of this pondered question at this point, IMO.
Of course it will "work". Where is Mary right now to chime in with the Circus Ponies when we need her!
The point is that it is not seen in MMA tournaments or competitions. I personally have not seen it, and I am betting we never will. I will refer to my points made in Post #3 as to why.
However, we do see some common themes in pins or submissions in MMA comps. Rear Naked Choke, Arm Bar, Triangle Choke, Omaplata, Kumura etc.
Why is it that we see those things commonly, yet there are other things we don't see? Why is it that we don't see Ikkyo?
I'd love to see someone go into the ring with the intent on winning and try that pin within the parameters of aikido practice.
Again, the principles are the same in MMA as to why the mechanics and physics work, however, the timing, situation, etc dictates as to why you'll probably never see that as a common submission (again I refer to Post #3).
If you spend some time actually doing MMA stuff it all starts to become much clearer and from my experiences you start to have "aha" moments with respect to your aikido practice!