A number of good ideas already have been mentioned, so I’ll just throw out my top one.
Revitalize the characters and their interactions.
In a franchise with over 400 episodes to its credit, there’s only so much they can do when it comes to creating different and unique criminal scenarios, so in the end, the characters and specifically how they interact with each other and the various suspects and victims is what makes a difference.
Get back to basics and remind me who these characters are and why I found them interesting in the first place. With the exception of Sid, I think every character was diminished in my eyes in some way this season. While I don’t expect these characters to stay exactly the same over the course of the series, they still need to have some core traits and behaviors that establish their identities, and when they deviate from those, there should be a logical, reasonable explanation for it. Instead, over the last couple of seasons especially, it seems the characters are being twisted and tweaked too much to fit the needs of a particular plot or storyline, sometimes seemingly without much regard for what has come before.
I agree with the idea of more two case episodes (or perhaps an A and B story for the episodes) but don’t know how realistic it is to do that from a creative and financial perspective. Looking back at the earlier seasons, the two case format allowed them to mix the CSI’s up in different combinations and show them working a case all the way through. In turn, this allowed the writers to explore more deeply the relationship dynamics between the various CSI’s (including conflict) and to show us the characters in a variety of situations (processing evidence, dealing with victims, interrogating suspects, etc.) which further helped to flesh out the characters. In contrast, now they tend to solve crimes by committee, which seems to foster a lot of exposition and more generic, group-type interaction.
Which brings me to my last point. The writers seem to be struggling with the size of the cast and how to utilize all the characters effectively. They essentially have six CSI’s now – including Adam, whose role these days doesn’t seem that different from that of Lindsay or Hawkes. Mac and Stella have become more and more administrative – walking around directing work, asking about results, and conducting the occasional arrest and interrogation – while the contributions of the other four seem somewhat generic and interchangeable. It makes the characters seem bland and dilutes their individual impact.
Given the current format of the show, perhaps they really only need three or four CSI types, one detective, and an ME to work most of the cases with a few recurring characters to deal with specific situations (two case episodes, cases requiring special expertise, etc.). Maybe they were trying to set up this type of scenario by putting Lindsay, Adam, and Sid on a rotational schedule, but it didn’t seem to work well because when these characters showed up, they still seemed to be mainly in supporting roles and not necessarily making a unique or special contribution to the case.
I’d like to see NY last at least a couple of more seasons and go out on its own terms, so I hope they can make enough changes to rejuvenate the series. Granted, my enthusiasm level is rather low right now, but I’ll occasionally check spoilers over the summer in hopes of seeing indications of changes for the better.