To pass some time in a train yesterday, I've copy'n'pasted my recent GPU ISP into Millipixels' postprocessing code to see how it compares with what was already there. Before/after:
Unlike Glowup, which takes about 30 seconds and lots of RAM to process, this is still just as fast - the photo is developed within 2 seconds from shooting.
There are still some crucial things missing, such as profiled denoising or proper highlight recovery, but since the performance budget for a still photo is much higher than for a 30 FPS video, there's plenty of room to add more stuff - and most of these 2 seconds are spent reading DNG and saving JPG anyway.
And the great thing is that you can take your past photos and re-develop them again with whatever code you have available now. No need to be picky, it's fast enough to just go through them all.