What part of "Reputation systems fail." aren't you getting here?
And what part of "They could be made to work with the right checks and balances" Aren't you getting here?
I suppose I left out the "checks and balances" part...
But look...
Rep whoever you want, whenever you want= Fail.
Rep certain people every few weeks to a degree representative of your rep, posts, and time spent on the forums= Not fail.