With regard to recent cases of deleting hundreds of posts from some users (justified, but still unnecessary), and banning users for something they did 4-5 years ago, I would suggest that posts should be reported to moderators max two years from time they are posted. I think it would be quite fair solution for everyone, if user is not punished in two years after posting something, it should remain in the past.

Some will certainly disagree with this proposal, but I think we need to focus more on the present or the recent past.