As for value for Cook, I still think the best plan is to try to swing a trade for Vernon Davis, straight up and presuming he would agree to an extension.
SF is looking for a vertical threat and while Vernon Davis is actually slightly faster than Cook, both are among the fastest TEs in the game and Davis is at the end of his contract and isn't likely to resign with the 9ers. With the 9ers in the basement, if they don't move him now, they get nothing.
As a fan, I can be upset with Cook, but he's been productive with inconsistent QB play and he's been a mismatch which is something that the 9ers need.
Frankly, BOTH need a change of scenery and while I don't think they'd execute this prior to their game this week, I can see this happening right after the game.