I would not mine this coin if there was not block reward voting. Other coins have chatting too, not true p2p chatting, but to the end user it looks similar. The block reward voting is a big reason why I like Talkcoin.
So maybe should be less radical voting? Like using some average beetwen the old votes and the last one?
Some kind of Gravity well but for the reward..
Build something like an IP check to make sure that no other vote can occurs from the same IP, that would block part of the cheating.