I'm not a programmer, so I have no idea how hard or easy it would be to implement this, but tangling with SaneGoat got me to thinking.
One of Sane's favoritest things to do is to create dozens of alts, troll everywhere, downvoat all responses, and then delete the accounts which deletes everything he posted, but leaves his voats intact.
It strikes me that a feature something like Wikipedia's tracking of all changes might be useful for holding such cretins accountable. Yes, he'll deny that this or that account was his, but right now, he can claim never to have said what was deleted all together, because it no longer exists. Whereas if, after deletion, the content was still available to those who wanted to reference it (but not "active" on the front page or in subs), that takes that crude form of impression management away and makes people a little more accountable for what they say.
I mean, yes, I could Archive.is everything he says when I interact with him, but that's nearly as annoying as he is. :)
So, feasible, or impossible, or somewhere in between?