Just one thing I wanted to address
This is fine if you are playing single player, but in a User vs User game your suggestion would be problematic. In this scenario, the double teamer's biggest weakness is he's turning his back to the man he's supposed to be guarding. In real life, that guy would be free to get open without his defender knowning. That doesn't hold when playing user vs user because both players can see the entire court. This is one of those cases where "don't play video games, play basketball" philosophy doesn't hold. So there needs to be
some leeway for post players when playing against other humans. This is even more problematic if the offense player who's not being guarded is just standing in one place (from your read and shady's, it sounds like this might've been addressed).