I think that's exactly it, and I think it's one of the reasons Blink is such a favourite; it was the first time we'd had a really timey-wimey story in nu-Who so it was fresh and intriguing. And because it was just one episode, there wasn't any need for character develiopment or continuity - I mean, Sally is a very engaging charater and I love her, but SM didn't have to sustain it over time.

There needs to be a balance between emotional engagement and plot - and right now, I don't think it's being achieved.