If she's got to go...
I want Carol to survive to the end, but if they do kill her I want it to come full circle from the first time she saved the day: producing Rick's hand grenade at the CDC. "Rick, I have something that might help."
Imagine the remaining originals from that scene - Carol, Rick, Carl and Daryl - caught in a tight spot and her saying that exact line again, with a little smile, just before sacrificing herself so the others can escape.