I think you're reply very probably makes Dan's point from my reading of his initial post. Which is that while Aikido, Kendo and Iaido may well provide a individual with an excellent skill set were he living in pre-modern Japan they would not necessarily be your first port of call were you living in a 21st century western country and your primary interest was in maximising your fighting ability for the enviroment you find yourself in.
Aikido may have been an appropriate vehicle through which Uesbiba expressed his internal power given the time and place he was born in but were he alive now and exposed to the present information available on the relative merits of different approaches to developing fighting skills then his Aikido may have developed very differently indeed.
Probably true. But my post was actually asking Dan how he would define the difference between MMA and cross-training. I happen to practice 3 arts which as you correctly point out would not be particularly beneficial to me in certain situations except in pre-modern Japan. That's just me however (I also like to play with BJJ and Judo guys when I get the opportunity from time to time incidentally). But, what about people who practice aikido and Tai Chi, or people who practice aikido and judo? Or aikido and BJJ.
How is cross training different from MMA? That's what I was asking really. I'm sure it is differerent, just not exactly sure how you'd define the difference.