Master Champ Skin

So I recently started to try and play Heroes of the Storm (friend ask me to) and one think that blizzard did but riot didn't do was that with their mastery system, when you reach the max mastery level with the "Hero" you unlock a "Mastery Skin" which is basically a buffed up version of the default skin, and I though this would be an excellent idea for the league mastery system because it doesnt really do much besides make the default bigger and stuff, it would work a little better from the croma packs. I know it would be a lot of work for riot to make a skin for every existing champ i mean it would be a process and Id be happy waiting