Do you really think that the Beeb would put Who up against X Factor? It might get moved back a bit as six is really too early. (Yes, I know back in the days my yoof, it was probably earlier.)
And, the ratings are a completely non-story. What do they expect launching at Easter in the middle of the most shambolically disorganised set of bank holidays for years? A lot of people have seized the opportunity to grab three weeks off for a minimal loss of leave days. Given the precision which goes into the planning of schedules (see last year's Who and the date of the Universe ending) I'm amazed that they didn't take this into account.