Aikido has quite few skill sets which would be relevant to the modern warrior; more than most jiu jutsu styles, mixed martial arts or kick boxing no matter how good the training might be.
This would be the only place I would not necessarily agree with Mr Ledyard. Studying Aikido for the past 9 years, I too agree that it is a very complete and comprehensive system grounded in years of tried and true principles.
However, in trying to convey this to Army troops, it has not been proven to be the most effective methodology of conveying critical martial skills to young troops that have little time or patience for training. In theory...yes. In reality...no.
I really don't want ot get into a nitpicking of this, because, as he so eloquently pointed out, that it is pointless to discuss which art is better..yadayada. Also, I completely agree with his statements concerning the facts concerning what the average person would face and there are better reasons to study than self defense and actual application of martial skills.
But, I do think he is slightly over critical of these other systems, and, at least for the U.S. Army, a mixture of BJJ, Muay Thai, Boxing, and MMA seems to be working when put together in a comprehensive and intelligent way to train soldiers quickly to gain some competence in basic martial skills.
At the same time, from my experiences, they are also gaining the same psychological benefits of discipline, confidence, and esprit de corps that come from just about any internal traditional martial art system such as aikido.
This does not mean that aikido is not effective, nor irrelevant, it is very effective and relevant, and the principles apply, even to soldiers in the Army. It is simply that the training methodology or model does not seem to be the best way to train the average soldier.