I think if it was another subject I would be less critical of it, thou I still say that taking it to Oz and setting it in London just doesn't work even for these kid shows
I loved K9 when I was younger, but tbh I preferred his role in Queer as Folk more than I have since his return in NuWho
He worked with 4 and Romana in a way that perhaps isn't really possible nowadays imo. His design is too clumsy for him to be part of the team full time so he's reduced to being the deus ex machina that flies in to save the day before disappearing off again