Some will certainly disagree with this proposal, but I think we need to focus more on the present or the recent past.
I have seen users were punished because of a sin they have done 3+ years ago. I think it was plagiarism. I am not against punishment but once a user establish themselves worthy and contributing the forum from long years the forum owe them. Punishing them for a sin that was done years ago is unfair.
I too think when reporters are reporting, they should deal with recent posts and when mods are moderating then they should not go back for x amount of time. I understand people will have different opinions.