Update for you…
I have been in touch with The Criterion Collection and it’s head, Jon Mulvaney, concerning and suggesting SUPERMAN, and got a prompt response promising he will share that suggestion with his colleagues at Criterion. And yes, I did suggest they include all three versions of the film (they did with THE NEW WORLD, which is also a Warner title). Considering I did this now since the 40th anniversary is December 2018, if they do go through with this, it will take a long time getting it all together.
The URL is criterion.com if you fans want to suggest this too.