Didn't expect a lot out of A14 tbh. I think that Operating Systems have matured to become mostly an intermediary between the user and apps as opposed to the conductor. As long as they stay out of the way, most users will be content.
Personally tho, I wouldn't be surprised if 15 is a huge release. Right now, the next frontier seems to obviously be transitioning phones towards AI personal assistants and w/ full integration. Microsoft is already leading the charge from the desktop OS front, but phones imo will be the most familiar integration opportunity.