When I think of old school D&D, I think of something like ToH or White Plume Mountain - it's about information, puzzles and rolling up new characters. I don't see the performance aspect looming that large myself.This is why grand pronouncements, or a unified theory of RPGs, seldom seem effective. What works (and may be true) for Burning Wheel or Prince Valiant may not be as true for Call of Cthulhu or an old-school dungeon crawl, let alone a modded Battle Tech.
As far as Cthulhu RPGing, I've been GMing some Cthulhu Dark recently and the invitation and response have been more important than the "artistry".
I can't comment on Battle Tech.