Good points! The core rules will be the same, but obviously (if anyone has been following the rules devlog) other subsystems have been tweaks or reworked to various degrees.
Something I'll ponder...
I also have the impression that talking about editions probably communicates a major change, but I'm not sure it necessarily implies incompatibility. Cairn 2e added mechanics, procedures, backgrounds, while keeping the core rules intact; although it could have been an expanded edition, I think 2nd Edition works well in that case as well.