It's not so much the characters I'm having problems with, it's the stories. Sure, there has to be artistic license, but these are supposed to be professional investigators and what they do has become totally unrealistic.
Decaying bodies lying in a room where everyone is milling around gets me every time, especially as there are never any bio hazard precautions. Likewise in the episode where they had to sift through vats of sewerage. Oh, a crust has formed over the body, let's hit it with a hammer (all in the middle of a lab). A computer program, written in an afternoon, that can "virtually" reverse random decay and reveal tiny wounds caused by a murder weapon.
Spoiler\
And if anyone saw the dissolving bones episode, no explanation whatsoever of what the (tiny) woman who killed her husband used as a bath during her attempt to dissolve the body, and how she then moved that decaying body onto the beach without leaving any forensic evidence or being seen. /Spoiler
Only more of the lesbian angle could save it for me.