You present an interesting
idea, but honestly, it's not a problem in my mind.
It's more like real-world reputation than a caste system. Who's more likely to get quoted in a newspaper: me, someone with a PhD in the topic in question, or my crazy neighbor? If by some fluke we all did, which quote do you think a reader is going to take to heart the most?
Unlike a newspaper however, most reputation systems are user-controlled: I choose what level to browse on Slashdot, and e2's rep is more for user feedback than actual moderation, except in extreme circumstances. And there has to be some level of moderation to most large sites, otherwise the flood of information will drown its users.
Another point I thought of recently: On the Internet, anyone can start over. You can always create a new account, and start out from nothing. It's like being able to go bankrupt every day - it makes it pretty unlikely that people will be stuck with issues from past and changed behavior.
So while it's a good thing to keep in mind, I doubt your worst-case scenario will ever even come close to happening.
P.S. This node's title is misleading - reputation doesn't equal happiness.