What about coins that are time locked by some arrangement or another?
Yep, definitely needs thinking about. I'm not terribly familiar with the current protocol's time-locking mechanism, but isn't the 'time-lockedness' of funds recorded in the blockchain somehow? If it is distinguished in the blockchain, the funds can be ignored by any proposed recycling mechanism.
What about people that are living under a rock and never learn in time that their coins need to be moved or they will be distributed like candy among miners? Yes there are people like that in this world.
Here I have less sympathy. There can be no such thing as a truly responsibility-free currency. Keeping up to speed with what is going on with one's currency is, it seems to me, the bare minimum of responsibility to expect of someone. Especially if, as coin-recycling advocates usually propose, the time-frame involved is very long, and the efforts that would be made to inform all users of the protocol change would be intensive. Today someone can come along and post 'I had 100 BTC but I've lost my private key, I demand the miners send me another 100BTC'. Such a person would be rightly told to go to hell. I don't get why such a response would be inappropriate to someone who 'lived under a rock' during the, say, 20 years or whatever during which the protocol was being changed.
IMO any talk of "redistributing" bitcoin wealth needs to consider these and other scenarios.
Absolutely - it'd be probably the strongest protocol change bitcoin has yet undergone. Such changes should not be made lightly. They should also not be
dismissed summarily, and in particular, not with attempts to smear their proponents.