I guess that should work. You could generate universal camo that way if you run the discriminator multiple times each round on the camouflage rendered on soldiers in different environments and either average the discriminator results (to get camo that's good on average) or pick the one from the environment where the discriminator performed best (to get camo that's never terrible). It might be interesting to see which of those two choices performs better.

Edit: on second thought, the maximum version is continious but not differentiable, so you would want the version taking averages.