It's possible one of the regs won't be killed, but will be wounded or shaken by the experience so much that he/she chooses to leave his/her job at the lab. Lindsay could become a stay at home mom--she'd still be married to Danny, but she'd effectively be written off the show.
Yes, I don’t really think they’ll kill one of the regulars – at least not right away, but it’s possible they will use season six to introduce the new character (and see how she does) while somehow phasing out one of the regulars. In Lindsay’s case the stay at home solution is an option, but off the top of my head, I can’t really think of a show that’s done something like that. Characters who are married/engaged/involved do occasionally leave shows but seems like there’s usually a break-up, separation, divorce, or death involved so that the show and characters can move on.
basically, I think with the rush to marry Danny and Lindsay and give them a happy ending, they're both a little played out as characters. There's not really anywhere for them to go.
As an individual, I think there are still some interesting things they can do with Danny, especially if they go back to some of the storylines that were introduced in earlier seasons – his family and the Tanglewood connections, promotion and progression issues, his impulsiveness, etc.
With Lindsay, however, I think they’ve written themselves into a bit of a box. From a personal standpoint, she’s had a dark secret storyline, rocky courtship, marriage, and baby all in a relatively short period. While I think they can still get some mileage out of the new mom juggling work and family scenario, I’ve got to wonder how long that will last and what they can do next. Professionally, I can’t see her out in the field chasing down suspects and wielding a gun (especially as a new mom); nor does she seem to have the presence and interpersonal skills to be an effective interrogator or victims’ advocate. And in the lab, I can’t see much difference between the work that she does and that of Hawkes and Adam.
So what role can Lindsay actually play in this team, especially among the women? Stella is the maternal goddess type….She’s experienced, tough, and attractive, can hold her own with the guys, and even gets to be the nurturer when needed. And if the new CSI is anything close to her description, she will be smart, spunky, curious and attractive. (Maybe she’ll even be able to team up with Stella occasionally to create that girl power dynamic.) I’m not sure how well Lindsay will fit into this picture.
I would like to see someone that Lindsay had a good dynamic with. She and Stella have never seemed right together. Stella sometimes comes across as rather superior and smug with her interactions with Lindsay and I think Lindsay could benefit from having a female friend at work. It would flesh out her character without having it involve Danny.
I think Stella and Lindsay have had some decent scenes together but don't seem especially close. I wonder if MK and AB struggle a bit with their scenes because they’re not exactly sure what the relationship between them is supposed to be – close friends, big sis/little sis, mentor, etc.
Going just off of this first description, though, I wonder if the new CSI would have much in common with Lindsay. Of course, a lot depends on the actress and how the character is actually protrayed.