I thought we could create a thread to discuss all theories.
(To those wondering yes this is borrowed from Galifrey Base) but it gives people a chance to avoid spoilers and speculation if they dont want to see it.

Also those who are saying they hope River is bad. we know 200 years down the line that the Doctor trust her second to himself. he is on good terms with her so it doesnt compute.

These "all in one" threads sadly seem to die a quiet death