Don't blink, breathe or turn away from the freaky looking alien; the Doctor is well and truly back. After fragmented half-seasons and a massive 50th Anniversary celebration, Doctor Who is back on our screens with a proper, twelve-part series starring new lead Peter Capaldi. With its slight teases of the story arc and the usual intro-future-past start, Series 8 has been very much in the style of the early days of Nu-Who (fan lingo for the series post-2005 resurrection) and has led to some impressive viewing figures both in the UK and further afield. Although much has been made about how different Capaldi is from the previous, young-looking Doctors (he's older than First Doctor William Hartnell was when the show started), the real challenge he's got is becoming the face of a major franchise. Although Who was always favoured in geek circles, under Matt Smith's chin the show has gone from British curio to worldwide phenomenon. But while Doctor Who has never been bigger, it certainly has been better; with great success comes great complacency and beneath the fun cracks are starting to show. Capaldi is no doubt the best person to take the role and if his performance thus far is anything to go by he could make these points moot, but there's no avoiding Doctor Who is teetering at the top of a long spiral down. Here are ten reasons why the show could be doomed to get worse.