Well, at least we won't have been spoiled for the damn thing before we even get to see it, as can happen with trailers. Anyway, I actually think a retrospective of the older Docs will be nice.
Thing is, that trailer showed at Comic Con didn't have any spoilers, otherwise that would have spread like wildfire online. Yeah, I know Moffat threatened to throw a hissy fit if the trailer leaked, but several websites have written up descriptions and that doesn't seem to have awakened the beast. And the most spoilerific thing there is the implication that John Hurt's Doctor was involved with the Time War, which many of us were already guessing anyway.