Charlie Jane calls it:

Way back in the prehistoric era when David Tennant still piloted the TARDIS, we met a woman whose whole existence was a mystery. And then she died, right before the Doctor's eyes. Now, the Doctor's found a new woman whose existence is, once again, a mystery. And once again, he's seen her die. Is Clara the new River Song? Spoilers ahead...

Tonight's brand new Doctor Who episode, "The Bells of St. John," introduces Clara Oswald for the third (and probably final) time, after her appearances and sudden deaths in two of last year's six episodes.

This is clearly another one of Steven Moffat's attempts to deconstruct the "companion introduction" process somewhat, to keep it from getting boring. Rather than just another "bright cute person meets the Doctor and gets drawn into an adventure" story, Moffat wants to make the companion's introduction more fancy and more unpredictable -- which is a good thing, for the most part.

So the main difference between Clara and River, of course, is that Clara doesn't know anything about what's going on, and she's even more in the dark about the "multiple deaths" thing than the Doctor is. At the same time, Clara has the same kind of nagging, potentially universe-shattering mystery that made River Song work as a character.

And here's a prediction -- the reason why Clara appears to be scattered throughout time and space will turn out to have something to do with the Doctor himself. Because these sorts of mysteries always do. The Doctor never just stumbles on a mystery that is something bigger than him or completely separate to him. The Doctor will wind up doing something, probably in the season finale, that will cause Clara to become Jaggarothed. There will be a scene where the Doctor realizes what he's destined to do, and he will feel weird about it. You heard it here first.

The rest of the article deconstructing Bells of St John is quite good:

http://io9.com/is-clara-the-new-river-song-on-doctor-who-463992909

'Jaggarothed' is probably square on.  Somehow, something the Doctor does blows bits of Clara Oswald across time.

And I hadn't realized until recently just how formulaic Moffat really is.....

Moffat isn't ALL formula -- otherwise, it would be too predictable to be enjoyable.

But yeah, his setups lack the nuance of, say, The Walking Dead, Mad Men, or Breaking Bad.

Still enjoyable, just not as subtle.