What a refreshing welcome back to Doctor Who! I originally went in expecting to have to force myself to tolerate Bill ... only to find that she is pretty damn interesting! She feels like a balanced cross between Rose and Donna. I loved her characterisation, including the humour, and the emotion that Pearl can convey in both her expression and eyes. The story itself, though not anything to write home about, was an excellent jumping on point for any new fans of the show, and there were some really cool set pieces throughout.
It's been said before but it needs to be said again - without Clara, it feels like the Doctor can breathe and finally take center stage. I loved him teaching at the University and his interest in Bill. That was the sort of 'mentoring' Doctor that I've expected from Capaldi all this time. Him having a conversation with the photos of Susan, River - and the Tardis - was heartwarming.
The scene where Bill was about to get mind-wiped was very emotional too. The kick in of Clara's theme was absolutely spot on as the Doctor suddenly realised that he couldn't put someone else through what he went through. Pure brilliance.
Speaking of brilliance, the way that they integrated Bill's introduction scene from way back was incredible. And blimey - Nardole wasn't (overly) annoying! He actually helped facilitate the new dynamic between the Doctor and Bill.
Yeah, what a fantastic welcome back to Doctor Who.