I'm deficient in a good training school here (not a lot of full contact around here), and still looking as I hadn't had the opportunity for years and wanted to get back into it, but you are one of the few I know who point out the one huge downside to the ground styles common in one-on-one matches.

If you're down on the ground against guy A, his buddy B is whaling on you while youre a sitting duck.

Now I need to go read that book