Hmmm. Just playing devil's advocate here, because I personally prefer the cascading style and wouldn't consider using the Vista/Win7 style...
You did ask for input on how Classic Shell could be improved. I wonder how many other folks are like Andre and prefer the Vista/Win7 style? I doubt you really know since using Classic Shell with Win7 those people can always just shift-click the start orb and get the start menu style they want, the Win7 style, while still maintaining the other advantages that Classic Shell provides, right? What happens when you shift-click in Win8? (I have declined the opportunity to try Win8, since I'm happy with Win7, among many other reasons, so I don't know.) Anyway, I assume the people who prefer the Vista/Win7 style will choose Tihiy's solution for Win8 over Classic Shell, as I believe Andre does. I've wondered whether the two solutions can be used together and get the best of both worlds? You might also take a poll to see what kind of response you get to the possibility of choosing the Vista/Win7 style start menu as an option. I stress option since I'm sure there are others like me that would quit using Classic Shell if it did not offer the cascading start menu style.
Just something to think about.
Cheers and Regards