seedsa problem that won't be addressed with specific class selection is the fact that a lot of people aren't a certain skill level on all classes and shouldn't be allowed to offclass because it puts one team at a clear disadvantage
even if a pugchamp style add up menu was added then it would need a system where certain people only had permission to add on specific classes i.e. medic
edit to add:
im very much an example of this myself, if i get into a game with another medic main and one of us has to offclass then we're immediately at a disadvantage
To add on this if you're a captain and you ask someone to play the class you intended for them when you picked them, there's literally nothing stopping them from doing a 180 and just offclass. No sub system or class locks whatsoever. Its annoying for the captain and also for the players added since they arent sure what class their captain wants them to play either.