Yea, I can see the Avatars being like PP's Epic Masters. Would kind of make sense from a rules perspective so Wyrd dev team doesn't have to not only balance out the Avatars with eachother and other masters but if they made the Avatars as like mid-game upgrades, they would then have to work to ensure balance on the upgrade conditions. That's a lot of work that can be reduced by just making them "Epic", so to speak.
Course, if I had a choice, I'd like to see them as mid-game upgrades because I'd hate to see the normal Masters become obsolete if one can just take the super version.