The casting aligns with Steven Moffat's pre-season push for greater diversity, admitting the show needed to 'do better' and featuring a black actress in a lead companion role. Michelle Gomez's Missy, the gender-swapped female incarnation of the Master, continues from prior seasons and is credited by Moffat with paving the way for further boundary-pushing changes like a female Doctor.

Thematically, episodes deliver noticeable progressive messaging: 'Oxygen' directly slams capitalism as exploitative; 'Thin Ice' features the Doctor punching a racist and grappling with historical exploitation; 'The Lie of the Land' offers a political allegory on fake news and authoritarianism; and the finale includes the Doctor reminiscing about past relations with men alongside gender fluidity references. These elements shape character arcs, dialogue, and casting choices without fully dominating the narrative, which retains strong sci-fi adventure focus and received solid contemporary reception. Recent audience sentiment acknowledges these progressive touches—lesbian companion, anti-capitalism, fluidity—but contrasts them favorably against later seasons' heavier hand, noting they 'don't register as woke' due to Peter Capaldi's traditional older white male Doctor.