Interesting algorithm but at the end of the day, a hidden function that determines who can play what is detrimental to the make-up of casual TF2. While on a more serious or try-hardy pub where you're stuck on the team with nothing but support classes and you guys can't push, the best mechanic is an updated team-scramble.
Biggest example of an improvement would be to take the person that made the most points and the medic that made the second most points be on opposite teams, while lending some kind of mix of this equation towards balancing the classes as they were at the end of the round before the scramble.
This would spread out the snipers and spies accordingly, and add positive classes to the losing team.
There are however some makeups of maps where these support classes are much more powerful, or have a stronger time on defense vs offense, so if valve retweaked the autobalance mechanics, they would probably favor switching defensive classes (demoman, heavy, engineer) towards the defending team on Payload and A/D maps, rather than mix them evenly.