A no energy required, sandbox type mode that nets you ally points per completion (10 points??? or maybe even 11 points???). Matchmaking could be similar to GW (based on your GP) with random teams of enemies or possibly meta teams. Even if they made the reward 5 ally points (or even 6???), that would give people something to do when they are out of energy and would probably only yield 1 piece of white gear, when you cash in the bronzium after 50 battles (I haz gud maths).
TL;DR: No energy required. Ally points rewards. Fun was had by everyone involved.