I am not a long term Doctor Who fan. It was the announcement of Peter Capaldi as the new Doctor that peaked my curiosity in the show, and had me watch all the episodes from the beginning of the "new" episodes in 2005 with Christopher Eccleston to the end of Matt Smith era within the period of a few months, having watched Time of the Doctor (the final Matt Smith episode) merely weeks ago.
I would now consider myself to be in the strange position of being well-versed in the world of The Doctor without actually being a fan. The show fluctuates between good and bad episodes frequently, with the "rules" of time travel and the functionality of certain devices (the Sonic Screwdriver being the worst for this) being inconsistent from episode to episode, rewritten as the show progresses, often as some kind of Deux Ex Machina in order to resolve the hole that the writers have written themselves into. I say this as a kind of disclaimer, that I am by no means a long-term fan of the show, very much willing to admit flaws when they exist. That being said, I seem to be in the minority when I say that Deep Breath was a good start to the new season.
The first Peter Capaldi episode of Doctor Who tries to keep things feeling familiar by having the episode set in Victorian England, supported by characters that viewers of the Matt Smith era will recognise - Madame Vastra, her wife Jenny and the Sontaran Soldier known as Strax, which (despite my hatred for Madame Vastra as a character) is a convenient way of giving continuity to the new season beyond Clara's continued assistance.
episode mostly deals with how Clara reacts to the new Doctor, mirroring
the emotions that Rose Tyler felt when Eccleston regenerated into
Tennant. As such, the emotional current of the episode will feel
slightly familiar to previous viewers of the show, simply repeating
something that we've seen before. It may be a necessary step for the
character to take - mourning the old Doctor before accepting the new -
but it isn't a particularly interesting step for the audience,
especially considering the lack of impact that Clara has made as an
show has needed a new
Doctor/Assistant relationship dynamic since Amy and Rory left in my
opinion, with Clara failing to really work as a character in the Matt
Smith episodes thanks to their relationship being a flirtatious one -
one we've seen many times before. This looks to be addressed here, with a
welcome shift in
the type of interactions between The Doctor and his assistant - there
have been promises that there will be a strict "no flirting" rule
between Capaldi's Doctor and Clara, which would be a refreshing change
and would hopeful allow Clara to become more realised as a character.
The "villain of the week"
portion of the episode is lacking, with uninspired villains doing
uninspired villainous things, but this can be forgiven as it was mainly
used to help define the new Doctor and shed a light on the kind of
issues the Doctor might be facing this season. There are hints that the
Doctor might have a complex around the amount of times he has
regenerated now, which could prove to be an interesting aspect of this
new Doctor to explore, certainly something that I don't think has been
looked at before.
The best thing this episode shows us is that Capaldi is doing something new with the role of The Doctor. Both Tennant and Smith (and I suppose to a lesser extent, Eccleston) portrayed "childish" versions of The Doctor, acting out to avoid confronting their past - it seems that Capaldi's Doctor will actually deviate from this formula thanks to the events of Day of the Doctor. It's nice to see that there is a real potential for change in the character of The Doctor here, while still very much keeping the eccentric aspect of the personality that defines The Doctor throughout his regenerations.
Deep Breath is the kind of Doctor Who episode that is to be expected from a new regeneration, serving mostly as a way to introduce the new Doctor, sacrificing plot and story in order to give the new Doctor a chance to demonstrate his new personality. Importantly, it shows that Capaldi will be interesting to watch on screen, and in that respect the episode has served its function. It won't ignite any passion for the show for new viewers, but it is hopefully enough to keep them interested long enough for this season to impress.