What do you think about dropping the possibility of double draw from Arena1? That'll help a lot for (a) making it more accessible to poorer people (so there's more of a window where a1 is an option prior to a2 and endgame grinding targets), and (b) making it different than a2?
It wouldn't surprise me if that change required a drop in a1 rewards (as it would get a *lot* easier), but that's fine.
Also open to other suggestions on ways to get *both* arenas to get plays. What isn't working is just tweaking the rewards, as it seems to be basically impossible to hit a point where one isn't better than the other.
edit: if 2x draw is removed from a1, serp just pointed out that that means every deck has enough points for 200 hp and 3x mark, so maybe remove one point from a1 (so that you can be 200 hp and 2x mark, or 155 hp and 3x mark, etc)