As I said, for *you* to force(!) *me* to reevaluate someone would be restricting my freedom in just as significant a way as a system-wide ban by an admin. Legislation of morality is a slippery slope. Give me the tools and let me use them, or don't give me the tools.
So, ignoring them for ever, would be a greater evil than you not being able to ignore them for ever.
Not to invoke the great Khasim-who-must-not-be-named, but I guess we'll just have to disagree here. My concept of evil is obviously different than yours. If I filter someone and they "truly change" (whatever that means), then one of the following three scenarios will occur:
1) I've been waiting for their return to sanity, in which case I will be actively monitoring them, and will probably have used a lifecycle tool like you propose,
2) I have found *some* value in their sane conversation, and will use social influence to reestablish communication with them when I see it. e.g. Ben might say, "you know, Twit X was just saying something useful the other day..." in which case, I would reevaluate the situation.
3) I couldn't care less about them. Ignoring forever would probably be best for all concerned.