While working on a generic RPG system I started to think to myself, can you make an RPG system that's built on a sliding scale? Like if you set your game to 1, you have maybe two stats - Physical and Mental - where you roll one die for task resolution, but later feel you want more depth and later slide that scale to 5, where your two stats have now been expanded (Strength, Agility, Presense and Intellect, Quickness, Charisma) and your roll changes to a group of dice with token modifiers. Do you think it could be done?
*ponders momentarily*
I probably could. The stats would be easy to do, but I could only have three (maybe four) levels for that. As for the increased rolling, the fun part in designing that would be keeping it from feeling cumbersome. Though I think you could come up with a logical progression of rolling as well.
HeroQuest essentially does this.