There's a lot of complaints here and elsewhere at the BBC's decision to include an extra disc featuring all the previous Christmas Specials for the Eleventh Doctor.
Please look at the price of this release.
That's the amount that it would have been priced at, even if the other specials weren't included.
The fact that they ARE included, and that the price hasn't altered at all, means that this release is actually great value for money. Plus it gives everyone who already has those episodes the choice to watch them on a different release.
I too have already got all of those other specials. I have them multiple times on multiple releases. It won't stop me from buying this one though, like the completist that I am.