I hope we really only get mechanical changes detailed and maybe some early gyms/pokemon. I really hope it comes out the same DAY everywhere so its easier to avoid champion spoilers and other such things.
Unless the game leaks early somewhere, I think it's highly likely everyone will be playing "blind".
Which would be pretty cool as the whole community plows through the game trying to discover all the Pokemon and so on. That's unless someone is able to hack and extract all the data on the Pokemon and trainers...
As much as I like to see all the new pokemon before the release, I think I might try to keep this one primarily blind (I'll probably follow news until April/May, to at least know starters' final forms)
One of the great things about Gens 2 and especially Gen 3 for me was discovering all the new pokemon. I spoiled myself on serebii for gens 4 and 5, because I lack self control when I'm excited about a game. Worldwide release will be great, as chances are only a couple other Pokemon will be revealed before then.