Thinking again about her episodes, and having just re-watched Heaven Sent, I really think that Rachel Talalay--in addition to her great skill and many accomplishments--appreciates better than any other directors from Peter Capaldi’s era just how visually beautiful he is.
I can't help it! I can't look away!! He's mesmerising!!!
Every time Louis stalks across the stage, or sashays through a hotel lobby, or drops a hip into that classic Michaelangelo statue pose he does, or moves in any way, this is what I see.