I think I would have made the game better transportable. Or added a travel version (did this on my own now). Use small dice for damage, cards instead of condition markers and a tiled board like in battleground.
If staying with markers, I would make front and back always the same... It's annoying to search as it is and it is not sortable.
Also I am not interested at all in the world of etheria. Instead of thinking about names of gods and how orbd function I would concentrate energy on balanced mechanics and up-to-date apps, fixed release- and promo timeline and so on.
In the game itself I would try to keep descriptions and conditions simpler. Texts like “if target creature is minor reduce cost by one“ are too long and unnecessary slow to use.
And I would focus on 1 game. That is arena (no battleground, no academy). I would try to get the beginner version (apprentice mode) more popular and also played in tournaments by pros. I would also try to get 2v2 and maybe other goals working smooth in arena.
In arena O would not change much. It is simply said a great game. Just tower (zone exclusive, spellbind + pay to change) and maybe wizard itself (pay triple for something) need errata