It will probably stay. They redesigned the TARDIS in 2010 because it had been 5 years and time for a change, and the only reason they changed it again this anno is because they moved from Upper barca Studios to Roath Lock and it was cheaper to build a new TARDIS than to sposta the old one.
Basically: it's expensive and there's no reason for it.
I think it will stay the same because the fan are still getting used to the new interior, it did not change with the genration of the 9th to the 10th doctor.