but would it have been underusing him, for him see Luke in action and recognise his brilliance? Plus allowing the Doctor to get into long streams of techno babble with Luke would be a very good use of the character IMO.from a plot POV Luke might have stolen a few too many of the Doctors lines and make the Doctor seem less amazing.
Agreed. When the spin off episode has the main character from the main series, you don't underuse him.
I was quite surprised at how well the Doctor & Cylde worked together, I was not expecting that.
Also Cylde turning up at Sarah Janes wedding, in suit similar to the Doctors, and with K9, great subtext.
I wasn't surprised, somehow I think I expected the Doctor would gel better with Clyde