While I do agree that the constant repetition of questions can be a bit much sometimes, especially so when the userbase is constantly expanding, I'm not sure having separate forums would change much. People are posting questions that belong in the How-Do-I forum in the general forum (this one) from time to time, for example.
You can't really stop people from posting very basic questions or posting in the wrong place. Even if there was beginner and advanced sections chances are people would post basic questions in the advanced forum anyway because they figure that the beginner forum is less viewed (that's a hypothetical situation, but a possible one). Then there's the question where to draw the line as to what constitues as beginner questions and advanced questions.
The way I see it the manual and tutorial sections of the site is what would be considered the go-to for beginners (even though advanced topics exist there), because the information that is usually asked for most of the time exists in those places.