I'm a member of the Doctor Who Columbus fan club and we saw the show as a group, we saw the leaked ep. of Rose and I remember thinking how short it was. And I really remember how good Billie Piper was seeing how she was described as the British version of Brittany Spears, but she turned out to be rather good. And I was alittle impressed by the new console room since it was a huge set. The whole series was upgraded, but as I said it felt very short a mere 45 minutes.
As a child (like I was at the time), 45 minutes felt long enough and much longer probably would have been too long for a child, and I'm pretty sure children and families were the main target audience for the show at that time. How things change as you get older. :P