I think it was quite fun, really. The monster in Van Statten's cage was now this mysterious sphere, that had come out of nowhere and destroyed the Time Lords - and the anguish the Doctor felt was that he had never found out what they were.
"I remember a scene where the Doctor is at last forced to kill it to save Rose - and even as it's dying, he's cradling it and begging it to tell him what it is. 'Shan't,' says the sphere.
Where they would have gone had they not secured the rights to the Daleks.