I think most current games already strike a good balance with the use of ratings, bonus quests and achievements. Basically anybody is able to complete the game by simply spending 8-40 hours playing, but getting a perfect rating, completing all the hidden quests and completing all the achievements will take the same sort of skill and dedication that those fabled games of old required.

As an old-timer with a job and a family I really appreciate being able to enjoy and make progress in games despite only having a couple of hours a week to play.