After some digging I found the ratings for last series - and Capaldi's series 10.
http://www.doctorwhotv.co.uk/doctor-who-series-11-2018-uk-ratings-accumulator-88397.htm
http://www.doctorwhotv.co.uk/doctor-who-series-10-2017-uk-ratings-accumulator-84045.htm
Jodie did better on first sight, but this was after the series had been moved to Sunday. Had series 11 been broadcast in the same slot as Capaldi, with much fiercer competition from the other channels, it might well have been a different picture.
I notice also that Jodie's stories were shedding viewers much more persistently (after a natural high due to viewer curiosity over a female Doctor kickstarting the season). From 10.54m to 6;48m in the space of ten weeks is hardly the success story that the media have been spinning. I suspect the BBC is now grateful that they only made ten episodes. The New Year special, with a hyped Dalek, did little to nothing to reverse this trend.
(Capaldi, in a much tougher slot - and with Moffat's Godawful writing to contend with - had a much less dramatic reduction from 6.68m to 5.29m over a longer span of 12 weeks.)
The BBC must naturally be concerned that her next series will pick up where it left off ratings wise, at 6 million - and then continue that downward trend. So I think there will be a lot of cosmetic changes to the show to try to prevent that from happening, whether Chibnall wants to make them or not. This might be why there is talk of unhappiness behind the scenes. The showrunner and his "five year plan" has come up against naturally worried bosses.
I think if they had kept Capaldi on and moved him to Sunday, we would be looking at much steadier ratings than the Whittaker era has (so far) acheived (no peaks, but at least no troughs) and I certainly don't think we would have had that dramatic slump.
I think it has been quietly agreed behind the scenes that "This ain't working folks" and preparations are being made for yet another new era to save the Who Cash Cow from oblivion. One sole episode this year is also no sign of a success story.
Maybe it's reached a point now, though, where it has been messed around with so much that and the public is so jaded with it that it needs another rest - and perhaps even a total reboot further down the line?
In which case, I am not certain whether they should even bother with a 14th Doctor.
But yes, if Jodie does regenerate instead of fading into Sylvester like oblivion then I think you are right about it being sappy and grandiose yet again. Perhaps she would be better off just doing the "Somewhere the tea's getting cold" speech all over again.