Different rpg systems provide different experience with their rules. Dungeon World is much better than DnD at providing a cinematic experience that just feels loose and fun. Even if you want a lot of clear rules, D&D is a really bad game at that, and there are better systems (Gurps does that and plays much faster for example). My favorite system in Burning Wheel which is great at bringing out character development and pushing the story forward really focused on what the characters are striving for.