Either turn the show soapie ("Vegas" is getting there - almost stopped watching thanks to Season Seven), consistantly screw up one of the better characters (hello "Miami"), or start doing ridiculous storylines. If they start making the show character focussed rather than case/evidence focussed, it'd definitely lose its appeal for me (hello "Vegas" and "Miami" again).
Yeap, only good CSI for me at the moment is "NY". Mind, I've only seen up to seasons 7 (Vegas), 5 (Miami) and 3 (NY). If "Vegas" does redeem itself, we'll see. For me, "Miami" is a lost cause. Pretty much stopped watching that, thanks to the Ryan storyline. I'm giving that show a second chance too. It's a 'wait and see' game, it it's all in the hands of TPTB.