Having things tied to the users karma will result in the StackOverflow type issues. There are some high score moderators that close questions that really should be left open. e.g. i don't agree with most of their decisions however i don't have enough karma ( or time to chase karma) to become the same level.

I see the necessity of moderating however there has to be other considerations. i.e a number of lower karma users can override the high karma users decisions.