They might use something similar to .hack's carry over method...

Darn, Yasunori Mitsuda's not doing the music this time around? That sucks. But the newcomers have pretty good soundtracks under their belts too, so it should still be pretty good.

As for the new look, I'm all for it. The cute anime look didn't really seem to fit the overall tone of the story. These new realistic models look overall spiffier and cooler to me.