I don't know if we'll see quite as many class books. In my experience, people "learned" over the course of 3rd edition not to use third-party rulebooks. If that's true of more people than just the folks I know, it might discourage a lot of rules-oriented products. Then again, maybe the fees for initial OGL access will raise a barrier to entry that keeps quality more uniformly high.
Locations seem like a decent guess, especially if they come with good tactical battlemaps. There should also be room in the market for more exotic campaign settings (or at least "setting options," like Beyond Countless Doors). And monsters and adventures are always welcome.
Locations seem like a decent guess, especially if they come with good tactical battlemaps. There should also be room in the market for more exotic campaign settings (or at least "setting options," like Beyond Countless Doors). And monsters and adventures are always welcome.