I will admit they change and depreciate APIs like crazy, but do you have any examples of features or AppleScript being jettisoned that were not fixed? The issue that stands out to me was the once in 17 year 2019 cut-off for 32 bit apps with a lacking Quicktime X and Final Cut X, but even then the plan then was to get everything back up to snuff quickly.

I read a Gruber article recently that when Messages went Catalyst he had no issues with his AppleScript at all.