One of PW 3.010's major novelty was the introduction of Horst's new image resizing engine that uses ImageMagick. Now I understand that ImageMagick can convert images to Webp, the image format that Google says can reduce image size up to 34% compared to JPEG.
Mozilla is apparently adding support to Firefox, and even the Safari team is playing with it, so it looks like Webp is soon going to be available in most major browsers. If Horst's module can be extended to add Webp conversion, that would be a great addition to PW's already very powerful image manipulation arsenal.
I'm currently using the free ImageEngine Lite to serve Webp images to supporting browsers, and the results are impressive. I routinely get images that are between 25 and 60% smaller compared to JPEG, with the same visual quality. I would love to eliminate the need to rely on a third-party service though.