I've just watched episode 2 and afterwards I had to go check the books: I was absolutely convinced that Mary Malone only appeared in book 3, but it's actually in 2, in the "right place" of the series.
She looks and acts very much like I imagined her, so I'm happy - that's one of my favourite sub-plots of the trilogy (still wondering how they'll do the Mulefa, do they have enough money for the CGI??)
I wish they'd tone down/reduce the whole Magisterium stuff, I'm sure it wasn't this bad/long in the books...
I'm also noticing there are a lot more daemons now, maybe they heard the complaints about season 1?