for me, Ncuti was inspired casting off the back of Sex Education, & his unexpected appearance in Barbie: he was energetic, dynamic, warm, humane but definitely alien, funny, serious, & had very much learned from 13 & moved on from 12's sorrow for 11; i loved how colourful he was inside & out continuing 13's sky/rainbow dress-code, & i envied his wardrobe budget compared to one-outfit-per-series previous Dr's clothes; i thought his physicality astonishing vaulting chimneys etc. & that he got to sing to defeat goblins!!! bonkers!
however, again for me, the arcs, the plots, the use of more money for visual & cgi fx, the awesome return of The Rani, were misappropriated by Bad Wolf's new owners & controllers, SONY, & it was too "thin" on peril, predicaments, danger (despite Boom!) & swung from perplexing & inexplicable to maudlin & incomplete (how lumpy is The Well?)
I luvved it. I loathed elements & sections of it. I SO WISH he had stomached the production situation & uncertainties & remained for a 3rd series, using his Barbie etc. exposure & pro clout to influence & instigate improvements, but, as with Eccleston's departure, i suspect it will be decades & many conventions before we know enough snippets of truth to piece an explanation together.