Texturing - I'm really missing something here.

OK, at the moment I use a tiling method to get smooth transitions from one terrain texture to another on my terrain. This is not a substantially different method from that used by Warcraft III. But... the tiling is a real pain to set up, and making it look natural requires a LOT of tile pieces. Another method I know of is to use a single great big texture file for the entire map. With this, you can do some really smooth and natural blending, but it comes at the expense of having really big map file sizes. As I understand it, this method is essentially the same as using a lightmap, except that it''s a full-detail texture. But now I''ve just seen the technology demo of the Crytech engine (crytech.com), and in that they show terrain texture painting that is completely smooth and interractive, and - given their map-sizes - unlikely to be method2 above. Enlighten me as to what I''m missing. Learning to fly is easy, but as a tortoise, the landings are really rough.