A black-list Black-list still hurts fungibility, which will destroy the currency. A black list may do more damage than a successful 51% attack.
Not if miners value their security, privacy and fungibility too. The idea is to discourage people from using "green" or "white" lists, as they won't be able to spend the money from their supposedly clean address. Make clean dirty.
Miners can play a role in this as Bitcoin users, but also by supporting mining pools and methods that promote privacy. They want to force people to use identified addresses so they can blacklist? What happens when miners start deprioritizing transactions that use addresses that have been previously seen?
I like this idea. Would require a lot of user education so they can understand why their transactions are not confirming. Would make asking for donations harder, but maybe that is a good thing.
Well, this is just a form of psuedo-blacklisting; making it difficult for the green/white addresses that get used to process their transactions, instead of outright impossible.