Broadly, you can divide Western thinkers since the Enlightenment into two categories - the top-down gang (who wish to transform and manage society from the centre, or top, on down) and the bottom-up brigade (who believe in very slow, unconscious and incremental social change, if at all). I prefer to call them "wrong" and the "right", respectively, but your mileage may vary. Anyway, you can also place roleplaying games into those categories, thusly - the idea being that one approach is to the attempt to legislate "from the top" (the rulebook) while the other is a small-state laissez-faire methodology which lets DMs and players come to their own conclusions when playing the game, within a very bare framework of rules:
Sydney & Beatrice Webb
D&D 3rd Edition
WHFRP 3rd Edition
GURPS (any edition)
Tunnels & Trolls
Interestingly, though these two categories can be mapped somewhat accurately to terms like "new school" and "old school" respectively, there isn't neccessarily a perfect correlation. Rolemaster is definitely a top-downer, for instance, while Blood & Honour is very much a bottom-upper. Also, while I consider myself a member of the bottom-up brigade (the more I write that phrase, the more it sounds like a homophobic euphemism of some kind...) there are some such games I dislike (The Window, Old World of Darkness) and some top-downers I enjoy (Rolemaster). Which just goes to show something, though I'm not sure what.
Perhaps this post is just a roundabout way of saying some games are rules-lite and some are not, but where would the fun be in simply stating that?