I have an idea to "save" the New 52 Superman. Create an Earth that's "adjacent" to the main Earth called "Earth B". It's not quite Earth 2 and it's not the main Earth but it's more of a divergent timeline that happened around 2014. All the stories that occurred in the New 52 Earth are canon there up to about Truth. A sort of "what if Truth never happened" thing. This doesn't necessarily need to have it's own title, just give him some back up stories in the main Super-books. Label them "Superman of Earth B" and move forward from there. It'll get fans of the New 52 to pick up Superman books again and those who don't like New 52 Superman can just ignore them. It can be kind of like Adventures of Superman or Sensation Comics. Out of canon stories that take place in one specific universe.