I would support some sort of collection of cards that makes the original class decks more playable.
I think that Print on Demand would work well for this.
I also have concerns about the viability of the class decks as the OP seasons progress. Will the characters and the mix of cards work well with the theme of each season? Season 0 has a lot of cards related to Skull & Shackles. How well will these cards work with Wraith of the Righteous?
Might there be a possibility of a generic or even character specific season upgrade pack which introduces cards that fit the elements of that season's base box?