SAFD: I grew up going to DL so America Sings is what I had always known in that rotating theater. I still remember the soundtrack!
I think it would be so fun if they rotated between CoP and America Sings, maybe every 6 months or so - I know it's not realistic, but that would bring back all the nostalgia for me. Since they used the original DL animatronics from America Sings to populate Splash Mountain, and since they are renovating Splash, maybe they could recreate America Sings at WDW!
As for CoP - I love it, and I love that Walt worked on it for the Worlds Fair, but it has always bothered me that they jump about two decades-ish between scenes until the last scene, which is a massive jump of many decades. So, if they could somehow make the jumps in time more even, ending in the present day, I would like that.