Very interesting post overall, and I'll probably write a longer response to it (short version - "have you heard of Greg Costikyan?"), but I just wanted to say -

"Not to mention the aesthetics of rolling lots of dice at once in order to simulate a really big fireball."

WOW! That's a really, really good thought. Thanks.

(You may not know, 'cos somehow it never made it to LJ, but I've been doing a lot of game design stuff over the last couple of years.)