Have a look at this blog post, for example, found via from the previous link. It correctly identifies the obvious current problem: Moffat sets up big story arcs that end with a pathetic, uninteresting and un-engaging deus ex machina fizzle. (And, I would argue, even the "stand alone" stories now frequently have pathetic resolutions.) From the last link:
Notably, both season five and season six end with a wacky aborted universe and a wedding. If there’s not a wedding and a wacky alternate universe at the end of season seven, I’ll be worried Stefan Moffat forgot to rip himself off. Now, I’m not saying Doctor Who should be a champion of stories that make sense all the time, but it should at least be consistent with its own mythology. The excellent Tennant/Davies era episode “The Waters of Mars” showed us the huge consequences (mostly emotional) when you screw with fixed points in time. These days that doesn’t mean jack shit, because the Doctor seems down with rewriting time whenever it suits the needs of the script.Rest the show. For 5 years.