[blasdel]

Applying your magic sort() encourages replies by users who want to play a game. That only works if those users exist and actually have useful contributions to make — both of those properties are much diminished outside the SO population.

You don't to rank answers unless you have unproductive bullshit in the replies. While programmers might love the karma stuff, everyone else prefers it if the bullshit was just not tolerated by the community and deleted by moderators.