I think it could work somewhat. It depends on the type of, in this case, subreddit. With this in mind:

> also demoted if their contributions are not good enough.

If there is a user that gains karma by karmawhoring with the quick jokes and whatnot he/she would simply be demoted by the rest of the high-users.

Or something to that effect.

Oh, would you only be able to vote in your classification and lower? If that's the case, doesn't that make it extremely hard for a crowd to overthrow a close-nit elite that refuses to upvote the plebeians?