I'm not sure how much I agree with your education system ideal.
There is a bit of an issue if you separate classes by skill level. For one thing, there already are 3 levels of math that you can take depending what your school offers. My school only offers regular math, because it's small. But if you go to a big school they have Essentials of Mathematics (which is very easy), Principles of Mathematics (which is the normal course), and Honours Mathematics (which is very hard). I'm not even going to go into the AP and IB programs.
The problem is that if you take Math Essentials you can only go up until grade 11 with it, and cannot write the Provincial Exam (which is standardized and is designed for the regular math course) meaning your options are limited.
If we did seperate everybody into skill levels, the school would probably divide into groups. You wouldn't meet nearly so many people if you only had classes with people just like you. Part of the fun of a class is that some people know the stuff and others don't. Then if you get stuck you can always ask somebody who understands it for help.
I suppose in the end it could work. I think the only way to know would be to trial it and see what happens.