That could work, but tbh I don't think you could stretch it so far to cover all of Diana's doings in the Injustice verse.
But thinking about a 3rd installment... maybe it's just me, but the whole Regime vs Resistance feels like it's run it's course by now and can't really offer anything new... so how about it if the next game's motivating factor is that half the heroes have been possessed by something... like Starro or Trigon?