4. Teselecta
This is almost an alternative to the Shadow Proclamation, but whereas the Shadow Proclamation would bring something old that we don't know know about, this would be something newer, from Moffat's era. We have no idea what Moffat has planned for season eight. Wit the rumour that Twelve may or may not be the last Doctor hanging in the air, we have no idea what will happen. There are still unknown questions about the Final Days of the Doctor when he will be at his worst. This could call for the Teselecta to get involved. If they truly are there to make people suffer for the crimes they have committed or are going to commit, Valeyard may be the perfect excuse to bring the Tiny Humans back. This would also be an interesting way for the Doctor to 'die' because they were, at one point, allies, and they helped the Doctor escape death once. To have them come back and try to kill him for deaths he doesnt know hes committed yet, but to have the idea looming in his brain that he IS going to kill these people at some point in a next regeneration would be an interesting angle for the show. While many regenerations mark the end of a Doctor, this regeneration could mark the beginning of a new one, and the adventures and challenges this new one will face. Tens regeneration was very much a goodbye to who he was, Elevens could be also be a welcome to a new body, a body that hasnt dealt with the profound lost that Eleven has. It is possible to look at Eleven like Nine Nine didnt have a choice in who he lost. Ten, though he lost people, the most people, for the most part knew he was going to lose the people when they did. Eleven lost the Ponds and Clara (twice) without seeing it coming, and weve seen that take an enormous effect on him (ie: the change in TARDIS interior).