It's not so much the Doctor..
...it's the writing and showrunners that I've thought needed replacing for a while. Capaldi has had a few really good moments (chained up with Robin Hood was a joy to watch) but has generally not had great stories to work with. The actors in the role have been pretty good in general, but some got better scripts than others. Jodie Whittaker has done well in both comedy and drama, and I have no doubt she can handle the role well, given a good script and story arc. I have not seen all of the most recent series, but I liked what I have seen of the companions. I was getting sick of every companion being the most important person ever with some universe-saving destiny. I want to see more low-stakes but fun episodes, not super serious melancholy fatalistic musing all the time.