Actually according to Day of the Doctor, Ncuti is exactly who the Doctor is supposed to be: "Never cruel or cowardly. Never give up, never give in." Using your argument it's the 10th, 11th, and sometimes even 12th, that have failed to capture the essence of the Doctor has they have broken that promise repeatedly

Just it the only reason you think Ncuti is bad for the role is because he portrays the Doctor as a decent person which, ironically enough, is exactly how the Doctor is supposed to be portrayed. It's in the name....

This story is pretty inaccurate. All of the Jedi who actually meet the Stranger don't live long enough to tell Yoda about it. The only one who does is killed shortly afterwards and is then blamed for what happens. Since Sol is dead, he can't tell Yoda that a potential Sith was involved.

Yoda is going to have difficulty preparing for a threat he doesn't know is there and definitely isn't to blame for not spending 100 years preparing for the return of the Sith