P: Generator JPEGs very poor quality

Oh, it does... just overlooked/misunderstood by a novice. 😞

You might like to update your WIKI to reflect the need for "module.exports = {" for .js files... and maybe add some additional clues that might facilitate self-help. Thanks though. Finally got it working!

For those still following along at home, the 2015.5 update includes a new image export engine and Generate can be configured to use it. The result is better JPEG quality and sRGB files.

Here's a summary of what you need to do, on a PC, to force Photoshop Generate to work properly.
https://github.com/adobe-photoshop/generator-assets/issues/348#issuecomment-231910466

The defaults will still exhibit the previous results, however, updates were applied to the FLITE transcoder for better jpg optimization.  You can set Generator to use FLITE with optimization via a configuration file.  Here are the resources you can leverage to do that:
https://github.com/adobe-photoshop/generator-core/wiki/Generator-Configuration-File-Format
https://github.com/adobe-photoshop/generator-assets/wiki/Configuration-Options 

Sadly, this does not seem to have been fixed in Photoshop CC 2015.5 - just released.

I have exactly the same problem. Also described here:
https://feedback.photoshop.com/photoshop_family/topics/ps-new-export-functionality-does-not-reach-im...
with Examples.

And BTW the new UI from the latest update is really bad.

My concern is that Adobe seems to be intending to replace SFW with Generate/EA; or to enfold SFW into EA (hence the insertion of the word "Legacy"); and Export AS is still missing a number  vital tools (including CM, EXIF options and comparative windows).

The poor quality of the EA-generated JPEGs (and the lack of better controls in the EA Panel including the embedding of the sRGB Profile) is a very strong reason for keeping SFW totally separated from the EA module.

So the issues with the poor quality from Generate/EA could directly affect SFW unless they are kept as completely separate operations.

Of course Save For Web is a fabulous tool (I actually never use Export As for this reason). But I think that debate is quite separate from the issues related to Generate. Generate exports Layer objects from PSDs as individual files. I can't see how this would be used for creation of resized images with EXIF data for Photography forums or correctly colour managed files which might be required for printing. Do you usually compose many of these in one PSD?

SFW is superior to EA for posting photographs (JPGs) to websites because conversion to sRGB can both be done automatically and the colour profile can also be instantly embedded in the JPG.

The better web browsers can read that profile and clients who need to download the file receive one that they can open, view and edit correctly in colour-managed applications (instead of getting a lump of Mystery Meat from EA dumped into their machines!).

The inclusion of full EXIF , or some subset of the EXIF, is often desirable when posting images on Photography forums on the Internet.

SFW provides these features (and a lot more in addition!) while Export As still fails to offer these essential tools.

SFW needs to be preserved as a separate entity from the Generate/Export As module; and it also needs to be returned to its top-level position in the File Menu.

Ann, I disagree. If sRGB was supported today I could probably utilise Generate for a wide variety of asset exports for use in website user interfaces and site population.

I have previously embarked on such a workflow when doing template design but ended up having to manually export in the end due to Generate's shortcomings.

With sRGB assets creation from Generate I would still be limited non-transparent, 256 colour, GIF files and 8-bit PNGs (due to lack of matte colour management support etc), but 24-bit PNGs and JPEGs would be fine. Naturally I'd have to tweak the JPEG quality settings to ensure the quality was okay. 

I'm interested to know for what uses Generate would be a time saver, when the export required other colour profiles and full EXIF. My scope for using Generate may be too narrow!