So many things to mention!
The Whispermen - well, I assume it's them - are apparently kidnapping Vastra, Jenny and Strax in order to force the Doctor to come to Trenzalore. That right there strikes me as a very dangerous idea; hasn't anyone ever told them that you don't try to get to the Doctor through the people he loves? But it'll obviously get him there all the same, because he's not going to abandon his friends when they need him. Plus, from some of the trailer clips it looks like Vastra and Strax have been turned against each other? D:
The Great Intelligence! Well, huh. It never really was properly defeated in The Bells of Saint John, was it? I wonder if this means it
is somehow connected to Clara after all, despite what I'd insisted earlier. I always assumed it wasn't because it didn't seem to realise she was important, but perhaps, if it was somehow in on this big universal plan that's going on with Clara Oswald, it was only pretending to not know anything about her, and was secretly... monitoring her, or something?
Multiple Claras! Are they really dressed as some of the Doctor's old companions?
That's kind of insane, but should be very interesting if it is the case. As for Clara being born to save the Doctor - well, that's good, isn't it? The Doctor shouldn't have been looking so bothered by what he'd learnt in She Said, He Said if the truth was that she exists to save his life in an epic way, surely? She can't even be dead as a result of it, because she's in series 8. Unless that's a different version of Clara, and the modern version we have right now
does die. Or maybe the Doctor looks upset about this simply because, though she doesn't die, whatever she does to save his life really screws her up in a way no human should have to deal with, just like Amy was screwed up with multiple sets of memories and Rory was screwed up by spending two thousand years as a Roman. I guess it's possible the Doctor might at least be led to believe she's dead at some point during all this; he's almost crying in one of the trailer clips, and Clara's (apparent) death is one of the only things I can see causing that.
The TARDIS looks all odd in some of these; there's vegetation growing all over her, and her central console seems to be missing. Probably a result of the Doctor crossing his own timeline in a big way? And also possibly how Clara is able to do whatever epic things it seems like she's going to do here. Heh; the TARDIS and Clara might have to put aside their differences in order to jointly save the Doctor's life, again.
River! I'm kind of wondering about why there's a gravestone for her, given that she wasn't exactly buried after what happened at the Library. I guess Trenzalore - which I'm assuming is the graveyardy place - just likes being creepy like that, or something. But, people think this is going to be a post-Library River? Hmm. Well, as much as I guess that might not be impossible, we do also need to have a pre-Library River in this episode at some point, because she needs to find out his name before she goes to the Library. And all this Library-related talk is giving me the impression that this'll probably be the last time we ever see River. :<