'[On ‘Smith and Jones’] Anyone who's interested in writing should study that script - it's one of the most technically brilliant scripts you'll ever get your hands on. The construction of it is dazzling, and yet - and this is the REALLY dazzling part - it's designed to feel light and airy and simple. And for that dim-witted reason, people think it IS simple. It's not, it's incredible. Look, what's folded away in all that gorgeous froth. A new main character, whole and complete - an old friend within minutes. Her entire background and family, all there for us, perfectly clear. And while all that’s going on, AT THE SAME TIME, a hospital gets stolen and taken to the (bloody) moon. All this in under ten minutes! And never mind all that, the entire format of the entire show is explained and sold to a brand new audience. Stunning. But - and this what makes your blood boil - because it's made to LOOK easy, idiots and critics think it IS easy. Try it! Go on, get yer pen, TRY it.

Thing is, I get a lot of praise for the complexity of Blink, and quite bloody right too. But because I know what I'm talking about, I can tell you as a matter of FACT, that Smith And Jones is WAY more complex. But because Blink wears its complexity on its sleeve, cos that was kind of the point, Smith And Jones conceals it, cos it's a means to an end.

Really and truly, Smith And Jones, go study. And if you don't think it's brilliant, shut up until you understand that it is.'
(From this post of Moffat quotes.)