I believe I saw one of the developers working on either giving those with low SP a slider or else at least warning message about voting power, so that's a step in the right direction.
You can always mute people. They can still comment on your stuff though... you just won't see it. I don't like to mute. That flag isn't permanent. People seem to take it personally, when really there's no reason to. If someone spams or trolls with a bad attitude and gets a flag, they can simply realize their mistake and make changes. Abuse of the flag never turns out good though. The next flag wars, with this added power... those will be bloody.
I was wondering how far mute went. I believe in tough love. I'd be a big fan of blocking. If I don't want to talk to someone I don't want to talk to them. Let them go somewhere else.