Why is multiple Scouts a bad thing? And for that matter, why is multiple Heavies a GOOD thing?
Demoman should be considered the same value as Soldier. Except at that point...Hell, even now, it doesn't take into consideration the fact that a player might run Demoknight, and thus mitigate the pushing potential Demoman normally has. So you have four Demoknights running around being about as useless as four Spies. I'm not even gonna begin with Pyro, and just say that a Scout is more valuable for pushing than a Pyro is.
It's all a moot point. All this system does is favor some classes over others based on an arbitrary sorting method (Heavy is apparently a generalist now?) and comes with the same problems regular class limits have (potentially keeping lower-skilled players on important pick classes and keeing higher-skilled players out.) The method isn't SUPPOSED to be based on skill level, but I don't see any advantage this has over just putting regular class limits. At 4 Spies, there's no combination on a 12 man team that will bring the point value to zero, and running 3 spies or snipers basically forces you to run only Soldiers and Heavies. And no Medics. Just putting a class limit on 2 Spies or 2 Snipers will accomplish the bare minimum this setup attempts to solve, though it doesn't address Engineers, but that's a whole different can of worms.
It's unnecessary work to implement and doesn't really solve anything standard class limits don't already address. Nor does it really rectify the short-comings of class limits.