I think tpowell was asking about the all-new autocorrect system. Do you have information on how that works, or were you just talking about the old system that is being deleted on Monday?
I have no evidence or reason to believe that the inputs to the corpus of valid word sources for the new system changed - most likely only the prediction model did. This misfeature only recently shipped (iOS 16, I think) and I’m sure Cupertino views it as a net gain.