In the old school days, characters were put in the vault and removed from tokens. But then at some point, they were added back in! I think that’s what should happen. So that certain 3s and 4s don’t simply disappear from tokens forever.
[And no, Vintage Heroics doesn’t count, because those may as well basically be called 2*-only tokens. If you’re going to offer Vintage Heroics, then offer more than a few chances per month for people to win them through play.]