I'd just like to direct you all to John B's post on what he means by the term Adventure Games, which captures a lot of what keeps drawing me back to classic D&D/OSR based games *even though* I'm not the greatest fan of some aspects of the mechanics. The procedures built into the game create a certain rhythm from which a story of adventure emerges *after the fact*. Of course, there is no reason why you can't 'proceduralise' other games which concentrate most of their mechanical energy not on 'the adventure' but on the regulating PC actions - as John B has done with Mythras. Anyway, here's a passage I particularly liked:
"The "adventure" then is not the narrative the player-characters flow through towards an inevitable climax and resolution, but the procession of problems, challenges, etc. they face; the decisions and deliberations they make about what to do about each problem or challenge; and the procedures they enact as part of those decisions, and the consequences of all the above interacting with one another."