Since I started GMing back in 1978 I didn’t feel the need, or desire, for a rules system to mechanically support the story aspect of the game. But if you do need that support, I have to wonder, why are you looking at OSR games for that? As far as I can tell the OSR is is a reaction against the Story-Game direction of the Indie-Revolution. So if you’re looking for games that provide mechanics for story development there’s plenty out there… but probably not in the OSR category. No? Maybe I’m missing something. That wouldn’t be at all surprising. :p