Also, the cover of the B/W2 guidebook was what revealed all eight gym leaders. But there's also this:
Update: An image from the inside of the guidebook shows a modified type-effectiveness chart in B2W2. According to the chart provided by the guidebook, Ghost-type Pokémon are no longer resistant to Bug-type moves. Note that this could simply be an error in the guidebook itself.
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ph33r teh masta~!