The TARDIS (acronym for Time And Relative Dimension In Space) looked like a London police box on the outside because it's chameleon system broke in an early episode (the first?) and it was stuck looking that way. It would seem a shame to repair the chameleon for a new series since that bit of lore was a main pice of shtik.

I really can't see the point of a Dr. Who series looking like one of the many Star Trek sequels. What would be the point? That's already been done and redone. No, we'll have to stay with the cardboard and string.

      - Mark