Otherwise known as the 'Doctor Who is too popular; how dare this quintessentially British show try and cater to the US market too?' More success means more money (particularly when it's broadcast outside the UK) and that's a good thing, because unless something drastic happens, Doctor Who is not going to run into the threat of cancellation like it did in the mid to late eighties. Its popularity (as demonstrated by the record-breaking worldwide broadcast on the 50th special in cinemas) means that we're getting Doctor Who for many more years, so you should perhaps not be complaining about anything that facilitates that. Doctor Who really is its own show. How many other programmes can have a gothic horror murder mystery one week and an action blockbuster the next? It hasn't changed because audiences outside the show are enjoying it. it's changed because Doctor Who is a show that is always evolving. It's still the staple show for great British actors, just as it was in the classic era; from the Doctor and his companions to great guest appearances from Michael Gambon and Bill Nighy. Up next... Judi Dench perhaps? Fans shouldn't worry: Doctor Who will continue in its very own style for many years to come.