I wouldn't dismiss GANs so easily. Yann LeCun was singing odes to GANs - as the most interesting idea in the last decade. The interesting thing about GANs is that they don't use a predefined loss, but instead the discriminator acts as the loss function for the generator - thus, it is learning a loss fn instead of using human guesswork to create it. That's quite a powerful new idea. Applications of GANs include making simulated images look more real, which is essential for RL, generating 'artificial' training images for other tasks and using the discriminator as an image embedding generator or classifier.