It will have SL specific descriptions (ie, history of X class in the Scarred Lands, how magic functions in the Scarred Lands, etc.). However, it will also have more generic character goodies, such as lots of new feats (and new types of feats, like Scion, Cabalist, and Bardic Tradition feats), as well as new PrCs (which admittedly have a SL flavor) and spells. There will also be NPCs, which are of course usable in any campaign.
So in short, there is a lot that is SL specific, but it can be worked into other campaigns relatively easily. Feats, etc. are less specific, and players desiring new options/ideas for Bards, Wizards, and Sorcerers should take a look.
-Michael Gill