Either way, the cat’s out of the bag (not Schroedinger’s Jon though ;-) ) and won’t be put back in again…
But as most of the episode 1 storyline was known before (with a bunch of scenes and pictures published by HBO), there are only two real surprises (well, more or less surprises depending on what you knew before): the Dorne storyline and of course the hyped "shocking" Melisandre event. I won't give away those spoilers here, but only discuss their implications storywise.
The first one seems to surprise lots of people; though it follows exactly the line I theorized about since having read the red carpet premiere reviews: "Elsewhere in the Seven Kingdoms, the women are taking control too – in some regions, terrifyingly so." That kind of said it all before, and Ellaria's expression in the last promotion video confirmed it for me. Farewell, Prince Doran.
The latter one is no real surprise for book readers and ASoIaF theory nerds; but how in seven hells do they sell this to the TV audience when they did not show a single of the many hints in the books before? I can't see how this shall work.
And more important: as "shocking" this may be to some, it does not give the slightest clue how this connects to the Jon Snow dead / resurrected topic. And how will this "set the scene for some powerful sorcery to come"?