I can understand most of the criticism, even if it doesn't bother me as much as it does some people. The big reveal about River was a bit hokey, even soap-ish, and a lot of the storylines didn't pay off -- the Silents were left hanging (har har), the explosion of the Tardis went unexplained, and Madame Kovarian was never fleshed out satisfactorily. Admittedly, I think a lot of the objections arose because people expected something more definitive than they got. But, at the same time, I don't think that was an unreasonable expectation. Maybe the season will hold up better in context a few years down the line, but on its own, even I found it a bit lacking.
The scene with the Doctor finding out about the Brigadier's death is a good example of the fannishness of it. As an old-school Who fan, I loved it. But for most folks -- even folks who have watched the new series since the beginning -- it must have been baffling. Seems crazy that a plot point hinges on the death of a character that's never been in the modern version of the show.