I think it is not a very good idea for the forums. (Just a note, I skimmed through the thread so correct me if I'm wrong)
If it is for a user (Not posts) then it will just be a way for users to anonymously insult someone without having to show their face.
If it is for posts, it could be useful though, possibly a good argument in the WEPR could be given reputation points or maybe a interesting thread or topic in the tavern could get reputation from users that like the thread.
However, if there is a restriction on how many you can give a day (Or even a week) I think the "+" and "-" system will work much better. Or even better, you can only say "+" and "-" each user/post once a day. That way you won't have people bombing the "-" button.
I can see this ending up like youtube, where it all depends on popularity rather than the actual content.
For the comments it would be great though. Someone wrote a merit worthy comment? "+" their comment and a moderator can see them.
Just my 2 cents worth.