I thought I'd throw my thoughts and ideas regarding the second half of the series into a post for y'all to ponder on. I expect that many of these ideas will be wrong, but posting into the MTTU forum, as if my guesses turn out to be right, they could be classed as spoilers.
First, in the very first episode of the series, the Doctor was killed...
[spoiler]
With all the 'ganger' action in the first half of the season, could the 'dead' Doctor be a Ganger?
Pros- The Doctor isn't really dead, and there will be another series!
- The Doctor told his Ganger that he would retain some part of the Doctor when he 'died', why would that line be there in the script unless Moffat wanted to bring him back?
Cons- The Doctor began to regenerate, can Timelord Gangers do that?
- When he died, the Doctor didn't revert to gloopy flesh. The Doctor has stated that TARDIS travel 'fixes' gangers, so this could be the reason, although Amy's ganger had travelled a lot in the TARDIS and could still be liquidised by a sonic burst.
[/spoiler]
We now know that River Song is Melody Pond, and has Timelord DNA from exposure to the TARDIS when conceived...
[spoiler]
Assuming that River is human, this means humans can become Timelords. Maybe River's son could become Rassilon, and therefore, Amy is the mother of the Timelord race.
Another option is that somehow River's DNA has some Timelord in it, and that either Rory or Amy are descendants of a Timelord (ignoring Pythia's Curse for a moment), and that this is another manipulation of the Doctor by the Gallifreyans.
[/spoiler]
River Song can regenerate, even though regenerations are controlled by the Loom and the Matrix on Gallifrey. These rules, however, no longer seem to apply, as the Master ran out of regenerations a while ago (the Daleks apparently took his last one in the Doctor Who movie, but he's regenerated since), and The Doctor has regenerated several times since Gallifrey was time locked. Does this now mean that there is no limit to the Doctor's (or River's) regenerations?
Anyone have any thoughts on these points, or have other 'predictions' they would like to share?