Hmm, I am not up-to-speed on the modern FMA fic scene, so I can't say much for the volume of '03 longfic that is about currently; but in terms of older fic, there is a fair amount. It depends on what kind of fic you enjoy, I suppose.

But even as a hardcore '03 fan, I enjoy reading fic based on the manga or even Brotherhood. A good fic is a good fic, after all! :)