The episode seemed to lack a decent story, just appearing to be more like a series of loosely connected sketches.
It did have many nice little bits, but lacked continuity. I did like the wooden Cyberman, and I'm sure there are other novel bits, I need to watch it again, although that may just highlight the inconsistencies and plot holes.
It was always going to have to be a bit contrived, to solve things like running out of regenerations, but it does seemed to have made rather more of a mess than you'd think was strictly necessary.
If we have to wait until Autumn, that's rather poor. We've been waiting for quite a while recently anyway, just getting the 50th anniversary and this Christmas special. I'm afraid this Christmas special has really let done the recent history of many good seasonal specials.
Ah well, where are the CD and Blurays.