The Tenth Doctor TARDIS set is basically about a third of the size that it was - there's a very small section of the wall compared to how it was (previously it was a pac-man sort of shape, now it's more the inverse) - it's tiny compared to how it used to be. Plus all the crawlspace (that was barely used in the show) underneath the console is gone, too. It's why you basically only see the set from one very tight, very specific angle in Day of the Doctor.
In an absolute heartbreaker the 2010-13 TARDIS is gone, too, as it was built on top of the Torchwood hub, which had all concrete foundations, making it nearly impossible to move. The actual console area survives, and there's two relatively accurate replicas of the console part around, but the majority of the actual set was destroyed when they had to take it down.
That was what forced the set change at Christmas, too, they were moving studios. It would've been as expensive to remake as to make a new one, and Moffat knew he wanted the 12th Doctor to have a more machine like interior, so he just made it change sooner. The original plan was probably not to change the TARDIS until the 12th's era, but production realities.
At least the console is safe. The BBC should really bring that in.
