Obviously an unpopular opinion, but I would love to see CoP revamped. We keep changing (and advocating to change) only the last scene, but if that last scene were "modernized" again, it would leave a huge gap in between the earlier scenes and the final scene, with a lot of relevant & significant advancements left unexplained. I would love to see the CoP become a "living" ride, with the first few scenes being changed every few decades or so to reflect the passage of time. Rather than the 1900s, 1920s and 1940s, the attraction could be updated to cover more recent key eras (e.g. The moon landing in '69, the advent of the home computer. etc.) culminating in a final scene that predicts technological advancements ten or twenty or even fifty years from now. I think this would retain the original spirit & intent of the attraction more than just preserving it in amber, and making the occasional minor change (which seems like a recipe for CoP eventually "aging" out of MK completely) and including that hint of the future would make CoP more thematically appropriate to Tomorrowland.
Doubt anyone will agree here because I know this ride is beloved as is, but I think part of the magic of imagineering is that it allows Disney to revisit past attractions and continue to build on them, to re-contextualize the commentary Walt made so many years ago so we can see how and why it still holds true in 2017. Obviously that's not as necessary with rides like Haunted Mansion and others, which are "fantasy" rides, but CoP is a look at our history as a people (and asks guests to reflect on what this might mean for our future) so it feels like a different situation entirely to me.