Amazing how the same episode can provoke such diametrically opposite reactions ;D
It left me a little cold. Not because I found it boring, but because of...Capaldi. I'm still not sold on his interpretation of the Doctor, and I didn't find him to be a hands-down better actor than Tennant or Smith this time.
A little too casual IMO.
But this episode did offer a fair bit of food for thought...
The way the Doctor basically sacrificed that rebel soldier to the robot "antibodies" so the others could get away was pretty dark. But we've seen that in him before; the Fourth Doctor evinced a similar attitude it on a few occasions.
Whatever the case, it shows we're back to a Doctor with not-quite-human morality.
The Doctor is fundamentally right, IMO--there's no such thing as a "good" (i.e. truly benevolent) Dalek--at least not yet. Even before the Doctor repaired "Rusty's" radiation leak, its (do Daleks even have sexes/genders?) first impulse in response to its newfound "goodness" was to lash out at those that would destroy all other life i.e. "proper" Daleks. Basically a Dalek eco-terrorist ;) And seeing the deep hate the Doctor carries for the Daleks only seemed to cement that attitude in Rusty's mind. No Dalek Sec here. But, surely, somewhere deep inside, the Doctor carries a little spark of satisfaction that this one Dalek could be the vehicle for realizing his darkest dream...?
Clara has come a long way in a remarkably short time. There's definitely an added maturity to her that wasn't there before. She sure seems to be moving fast with regard to finding a new boyfriend. And that slap...totally redefined the relationship between Clara and the Doctor. He sure won't be able to treat her as "little girl lost" anymore--and I don't think Clara sees herself that way any longer. (Who else has hit him like that before? River, Jenny Flint...)
So why wouldn't the Doctor take Journey on as a companion? Does she remind him too much of himself, especially as the War Doctor? The whole "you mean well, but I wish you hadn't been a soldier" bit.
I think what I didn't like the most was the revelation that the Dalek shell has an emotion/memory suppressor, similar to what the Cybermen are equipped with. It detracts from the idea of a creature bred for pathological hatred. They can be made "good" just by pressing the right buttons, as it were. (But see above comment)
cheers,
Gabe