I've always thought they should do something like that. Merge everything and show the real superman which for me it was PC earth 1 Superman. That somehow after the first crisis he got split. I would not like the idea of merging also E2 with E1 those ones should stay separated.
I am sure this will make Carver's butt hurt more than usual and it will be glorious to see the fist post after the merger.
As for the whole story being canon as of right now. I am not so sure, there have been plenty of retconed stories from PC mythos into the modern Superman especially on the pages of the JLA, but from his main book there hasn't been that many retcons mentioned like the first fight with the Galactic Golem. But that is my take on it anyway.
The best thing will be to see Carver to roll down under his bed curl and suck down his thumb if this merger happens! 👆 😂
Also it will be great to make a meme of Superman and Thor.
Superman: hey bro, how is it going? Did you know I just got all my history back? Have you got your hammer back?
Thor: ðŸ˜_ðŸ˜_ðŸ˜_