It really feels like they are steaming through the companions... Now it might simply be that the number of stories remains about the same, its just that the old Who ran a multi-arc serial, and nu-who has a different story each week. But I rather miss the old days when just occasionally it wasn't a story arc ABOUT the companions but that it was about dropping the Doctor and whoever was in the Tardis into a situation to solve...
Oh well. Maybe I would be happy if they could decide if the doctor wants to be all woeful and travel alone or pick up a companion. We seem to have both... "I take you along so that I can share the womnders of time and space, but its bleedin' dangerous, so I will take you home again..."
One thing in favour of RTD. He was the first to go back and revisit old companions and the affect the doctor had on their lives in Class Reunion (and again in the Sarah Jane chronicles...) Which made for a good bit of dramatic pathos.
