Finally finished the third season last week. Got behind a lot, because I only found out it started again a day or two before the cancellation, so that was a wild rollercoaster.
All in all, I loved the season, especially the new characters and their interactions with the old cast. I thought Anna would be extremely dull at first, as a goody two shoes and thought she was only introduced as a moral counterweight to Errinwright. But her later arc really gave her depth and her friendship with Amos (gotta love that deadly teddybear) is shaping up to be something special.
I also love Ashford. His accent, his mannerisms and the fact you never knew if he was going to betray Drummer (<3) made him really interesting. He also fits perfectly in my list of characters that I love that are grey-ish and play on another level, such as Roose Bolton and Littlefinger (before they ruined him).
And of course the return of Miller. Fuck. Yes. Baby. He was my favorite character until his heroic death and I was so glad he was back, even in a minor capacity. I really hope he will come back in season 4 and onwards as a sort of compass for Holden. Let's what they can make of the new worlds with an Amazonian budget.
The question that I don't think we ever got an answer for and maybe was no big deal (or I just missed it), in the very first episode before the Cant gets destroyed, Holden's girlfriend says "There's something you should know" and then dies. I was waiting the whole series for what she was talking about!
I think it was a classic "Jim... I'm pregnant."