I agree with you, Kat. If they did that and talked Billy in to coming back for the entire season with the promise that it would be CSI's last season, then I think the ratings would go through the roof. At this point, I'd much rather it be CSI's last season than to see it go down a rockier path every season.
They could even make a third spin-off (spun directly from the Vegas version) to make up for the loss. Of course they'd need new writers, but they could still use a few of the original characters plus new ones. Nick and Greg (and I'd love for Riley to be there too, but that's just me).
I'm sure once CSI Vegas ended, Marg would most likely want to move on to other things. LF can always go back to doing movies since he's a big time movie star.
Personally, I think they should do a spin-off with Brass and Nick. Those two work great together. They could start a P.I. business and make Greg do all the grunt work (like Nick had him run something to see how much time, ok, my mind is so not working and Grissom had him find that soda bottle). :lol:
Oh yeah, Brass would definitely have to be there. :lol: