How about a different solution?

I seem to remember a few years ago it was necessary to remove the game threads because it was thought they were slowing down or causing some issue with the way the site was running.

The act of pulling the thread immediately dropped everyone's post count who posted there. I guess it was the equivalent of deleting the thread.

When it was put back the post counts did not return.

Wouldn't it be just as easy to simply pull those threads in where people have thousands of posts and then put them back?

This might be easier than having to deal with exceptions and grandfathering.

Or, better yet, the easiest of all would be to remove the evangelist title all together.