And it is:
Inebriation.
Read no further, lest ye be spoilered.
Having seen the preview, my original guess was that Morressy was going to turn out to be a conman, and Rosita would die in his arms at the end, causing him to turn over a new leaf. That was completely wrong.
I am kinda sad that Morressy didn't turn out to be a future Doctor, because he was brilliant. Can we keep him anyway?
The Cybermen seemed to be written more like their classic series selves. I approve.
The Cyberking sequence was great. I'm almost surprised they could afford that.
Seeing the clips of the original Doctors = BRILLIANT. McGann is canon, oh yes!
Roll on Easter or whenever the next special is playing.