I think Moffat brought some very interesting concepts into Doctor Who. Such as the weeping angels and River Song during the Tennant era.
However, I felt they lost so much once they were fleshed out. River Song started off as this idea of someone who was larger than the Doctor and that the tragedy was that we were seeing a River who was in love with a Doctor that loved her, yet it was never that Doctor she met.
I think we've seen River's time line play through the show, and the most I ever got out of the Doctor/River relationship was that 11 simply put up with her; there was no actual love, just an infatuation on River's part. If anything, it felt like 11 was annoyed with her if she wasn't behind bars.
I liked Matt Smith, but I think we got too much goofy Doctor. I have a feeling (I hope) that a lot of the past few seasons were written for Matt Smith's Doctor and that the feel of the show will change with Capaldi.
The more I think about it, the more I think that the whole River thing was a load of shit. I think that there was a lot of potential with her but by the end of her story I had completely forgotten what the point of her was.