He just has a habit of serializing DW and you can see elements of his writing carry over from season to season. He plans it out much more than RTD ever seemed to. As for the Girl in the Fireplace connection, I believe you can see the return of the creatures from that episode in one of the series 6 part 2 trailers.
I thought it was pretty funny that Moffat's very first script as show runner was a rerun of "Blink" 