That's disappointing :( It would have been interesting for the Doctor to have dropped in, not necessarily to help out or anything but just for a little Doctor and Jack interaction. But at the same time it's understandable. Torchwood crosses easily over into Dr. Who but I can't see Dr. Who crossing over as easily with Torchwood. Still, it would have been interesting since Torchwood was started with the Doctor in mind as the enemy.