Mastery Prestige on Reworked Champions

So I'm currently challenging myself to get as many champions possible at Mastery 6 and 7. Going to have difficulty getting that much Blue Essence but that's an issue for later. The goal of this challenge is for me to have some semblance of proof that I have mechanical proficiency over a wide range of champions (As I say this with 7 of my 12 Mastery 5+ champions being simple Fighters, and then 8 counting Master Yi. Shush I know). However, it occurred to me, what if one of these champions got reworked?

An easy example is the complete overhaul that was the Galio rework. Prework Galio and Reworked Galio are two completely different champions, and waving around a Mastery flag on a champion I'm effectively playing for the first time feels...wrong. Not only this, but especially what with Mastery being a sorting option in Champion select, or in my personal case a representation of my experience on that champion, it could just be flat out misleading. It doesn't even need to be a complete overhaul really. Gangplank really had two abilities significantly change over his Rework. His Ult is upgraded (well, can be) and a lot of numbers were moved around, but a lot of what made Gangplank Gangplank is still there. Despite this, Gangplank's barrels adds such a dramatic dimension of play that even beginning to pretend being a master of old Gangplank is anything like mastering our current one without practice is just wrong.

Riot has stated before that they will not be resetting Mastery points for champion reworks. I don't know if this is because they don't want to force a reset on player progression, or if they don't want the reset at all, but I think leaving an option open for that could work out. A prestige system, ideally. This doesn't JUST need to apply to champion reworks mind you, champion reworks are just what got the ball rolling for this idea. Effectively, I can cash in all my current Mastery points for whatever trade in Riot deems acceptable. Maybe if I cash in from Masteries 1-4, I only get a slight bump in how many Mastery points per game I earn. Or if I cash in from Masteries 5-7, I can gain cosmetic bonuses like an added effect to my Mastery's loading screen banner, or a border effect around that champion's icon. There could even be bigger bonuses for those players with absolutely ridiculous Mastery scores. Not only does this give a much more accurate way to gauge progression on a reworked champion, but this could continue to reward players who have gone above and beyond on any particular champion but currently aren't getting rewarded for that because they're already at Mastery 7.

Whether you're here for more accurate representations of mastery or getting extra "free" rewards for putting in lots of time and effort, I really hope you consider if you would use a system like this that continues to reward devotion to your Main, and the time and effort you put into that champion.