Thorton makes a (generally) good argument for stress testing and randori, but fails to mention that ALL MMA, BJJ, and JKD use drills to develop motor skill responses. Drills ARE kata!
Another thing I noticed was the emphasis on getting the person trained the fastest, comparing groups trained in the "traditional" way, the "alive" way and those not trained. He theorized that the alive group would become "effective" faster and that the untrained group would probably be better off than those trained for a short time in aikido. Again, that's assuming that the aikido training was as he defines it, dead.
My teacher told me to "teach as much as possible as fast as possible," and to "teach something at every lesson that they can go out and use that very day."
From those instructions and my experience in aikido and the broad yoseikan curriculum, I developed my Zero Degree teaching method, which I think is extremely good for quick development of self-defense skills without the student's feeling like he's doing a lot of self-defense training.
Anyway, all that aside, there is still the question of what happens "long term"? It seems to me that BJJ has shown long-term effectiveness and relative safety and that it can be practiced by people of a wide range of sizes and weights, so that should not be a problem, depending on several other concerns. The JKD, in my mind, is far less valuable.
On the other hand, when I think of some of the long-term American teachers of aikido I've known, it seems they are far more likely to get progressively less well conditioned as they age. American aikido teachers I've seen tend to get fatter and less active as they age. I remember one 6th dan I saw who drove in from another city and did a demonstration. He did a very brief and terribly unrealistic looking randori with a skinny man and a small woman and at one point, the teacher almost blacked out. He had to stop the randori and bend over and put his hands on his knees to recover, right there in front of everyone. And he was considered a major instructor by most of the group in attendance.
This is especially bad when you're a "major instructor".