There isn't a single player I would be too worried about losing, but I would be worried if we lost them all. I think some continuity is a good thing, even from a disappointing season. In roughly this order, I would like to keep some combination of:
Kam
Chandler
Moreno
Lowe
Hawthorne
Dioubate
Jelavic
Time to let loose BG, and I feel certain Jasper isn't coming back regardless, but if I were coach/GM I wouldn't put much effort in retaining him anyway.
No time for Pope and the staff to mope, they need to get on the phone with agents today.
Edit: I forgot to even mention Noah, which should tell you about how much I rate his importance.