Steven Moffat, he's the series executive producer and head writer - the show-runner. Ever since R. Davies left, the show seems to have taken the hive dive into an empty pool over and over again. Don't get me wrong, I still love episodes of his like "Blink" and "The Empty Child", but lately everything seems a bit too messy/redundant/disjointed/emotionally bland/forced. Instead of cleaning things up, everything always seems to be swept under a "clever" rug, not even by him, but die-hard Whovians. Admittedly, I have fallen into that category many times, but unless the show stops feeling like Indiana Jones (and the crystal skull) on Nickelodeon/Disney, I'll stop trying to jump back on the Who-wagon.
I won't get into specifics, but if you would like some, just google "moffat betrayal"
Also, nothing against Matt Smith, he's a lovable "cool" guy. I really like his rendition of the doctor.