Why not allow refunds of reworked champions to those with high mastery on them?

As of Karthus' VU Riot has changed their refund policy on reworked content because majority of refund requests were from people who barely played those champions and saw it as an opportunity to get their IP/RP back - unfair to people who actually played those champions, but a necessary change in their eyes.

However, now that we actually have a system which more-or-less measures someone's devotion to a certain champion and thus separates actual mains/regular players from those who just want to go back on a purchase they regretted, why not tie refunds in with that? Say, a champ gets a gameplay or visual update and those who don't like it get a refund if they have at least mastery 5 at the moment of rework being announced. With lots of reworks reworks sadly known to mutilate a champions identity, looks or feel a system that can single out a champion's fanbase and give them an option to refund would be more than welcome.