I've thought some about this, and I would say moving to a reddit alternative is just pushing back the same issues a couple years unless there's some sort of decentralization. I think issues of censorship, privacy issues, and moderator abuse are going to happen once a substantial community is developed if there aren't mechanisms other than promises to keep them from happening.

A good example is Diaspora as a facebook alternative. (One that I really support! Add me as [email protected].) There is no one website to connect to Diaspora - rather there are "pods" which connect to each other. Anyone with a website can host their own pod to connect to the network. This way, anyone unhappy with moderation can simply switch pods without having to leave the network entirely. Right now (as far as I know) all the pods have friendly terms of service and good moderation - this is going to be mostly true because it's necessary for diaspora to survive at the moment. Similarly, alternatives to reddit are going to be more privacy friendly and not eager to censor anything - that's not a good way to keep a small community active. These will only be issues when the community becomes large enough that people are active simply because the community is large. If all the activity happens via a single website, it makes it extremely easy for that website to change it's values on privacy and censorship once their userbase has grown large enough.

This is why I'm not jumping ship yet - there might be communities which have good values now, but they're not places I can trust in the long run. To me, it's not worth giving up the big community unless I'm helping something that I want to catch on. That said, support Diaspora! It has enough life to be usable now, but every person contributing makes it a little easier for the network to keep growing.