...if you've watched the show for 9 years...
Just a general reminder - it's fine to disagree with someone about when/if one of the shows jumped the shark. I'm all for discussion so long as everybody plays nice.
However, let's not tell other people that their opinions are wrong. We may all be watching the same show, but we don't always see things the same way. What's awesome for one person may be way over the top for someone else.
*****
Personally, I don't think any of the shows have jumped the shark, but I think they've come close to leaving the dock on their water skis. So much of the stuff with Horatio on Miami seems utterly ridiculous to me, but at the same time I know it's a style choice and that it definitely works to pull in millions of viewers - so I don't know if it has jumped the shark or if it's a work of complete genius. (There's a fine line between genius and insanity and all that.

) While I think CSI has gotten a bit dull for my tastes in more recent seasons, I don't think there's anything that has really caused it to jump the shark.* For NY, I think it's more a case of being sloppy than really being desperate and jumping the shark. And while some things are just as bad as always (lord have mercy, the timelines are atrocious!) and some things are worse*, other things have gotten better (like giving certain characters more development, introducing some family issues, etc).
* The exception for both CSI and NY (and possibly Miami if they keep dragging out this Eric/Calleigh thing) is that relationships are a tricky thing. It's hard to write a dramatic long-term relationship without making it ridiculous in the process. Happy relationships aren't dramatic enough, and they have to walk a very fine line. They risk showing it too much or not enough, and ultimately, not everybody is going to be satisfied.
As far as relationships go on these shows, I think Danny and Lindsay have gone farther toward helping their show jump the shark than GSR (or the relationships on Miami). Yes, people have relationships and get pregnant, but I really see no reason why a show should utterly disregard logic, common sense and safety precautions in order to include
any storyline.
Yes, logically they can't get instantaneous results for every test or find a clean fingerprint on any surface, but for me personally, I think there's a difference between bending the rules of logic for storytelling purposes and bending the rules of logic (and just the rules in general) when it comes to interpersonal relationships or to accommodate something like a pregnancy. (In my opinion, twisting the science is one thing, but the people should remain believable - otherwise why am I watching? I can watch a show that takes place in outer space, but the people should be realistic no matter the setting or the science.) The show should work around it and make it a part of the story, not just shove it in. That seems lazy and, as I mentioned earlier about NY, sloppy.
So in my opinion, by tossing out some of the realism that existed on the show (because let's be honest, it's television and can only be so realistic in the first place), they showed some desperation. When a show starts looking desperate, I'm keeping my eyes on the water to look for fins.