For those of them that are pro-K-9 , I simply have to ask this question ," Other than the pure sake of cuteness and the magic of John Leeson's voice, why ? "
I give that, yes , he is cute and it's cute in the Doctor showing affection for , bantering with and arguing with a tin dog . Unfortunately these reasons are not quite enough ( for me ) to make the K-9 case . The more I watch of K-9 in the stories the more I'm convinced that he became a crutch for the writers and less of a real character . I mean really, how many times did we see the Doctor get out of a sticky situation because a well timed zap from K-9's nose only to then endure the inevitable dying battery scenario ? How many times did we have to hear the the question, " K-9 are you fully charged yet? ". They seem to have wasted a whole lot of time in stories repairing, tinkering , charging and wondering about K-9's health and when another close call for the Doctor reared it's ugly head -TA DA- the dog was back to " full capacity" to save the day ! However did the Doctor manage to get along for 750 years without K-9 to save his skin ? Before K-9 how did the writers manage to write a scene where the Doctor used his own wits to save the day ? Oh , wait !
That's right , they had to use that rusty old thing called a creative imagination and that made it a lot more fun and interesting to watch than doggy zaps