I think the obvious answer to why the show is sucking is obvious. Ever since Steven Moffat took the reign in the latest episode the ratings jumped ten fold.
Moffat is great in writing single episodes (I mean, The Empty Child and Doctor Dances are my all time favourite episodes from the first season of this revivaled series), but the seasons when he was the show runner didn't impress me much. Maybe the show had ran out of steam by that time.
Moffat does seem to work best when he hasn't got the whole show to think about, arcs etc.
I was looking forward to his return to see how he would do without all the pressures of being the show runner and while it wasn't my favourite of his episodes he didn't disappoint either.
Funnily enough my favourite RTD episode is Midnight which is basically a standalone episode without the pressures of a series arc