I think Gillis is waiting to see if Raymond can rebound to start the season.
It doesn't make sense to trade him right now when his stock is this low. Hopefully he can find his game, but if he doesn't, you can move him early in the season for the same return (nothing significant) that you would get now.
The problem is that Alain Vigneault doesn't respect Cooke. AV doesn't mind agitators - as long as when they instigate something they are willing to answer the bell and stick up for their teammates. Remember AV is a former goon and he knows the price the heavyweights pay when guys like Cooke cheapshot people and then turtle.
I recall once incident in a game versus St. Louis shortly before he was traded - Cooke slew footed the St. Louis goalie when he played the puck behind the net. Initially there was no penalty called, but Eric Brewer grabbed Cooke, dropped his gloves and started throwing punches. The linemen separated them and the only penalty on the play was to Cooke. Brewer dropped his gloves and was wailing on Cooke, and Cooke got the penalty. The refs don't respect Cooke either.
I can tell you that Cooke was not well liked in the locker room his last time on the team. A couple years ago I played against a former enforcer for us and he mentioned to me that he had to step in and fight for Cooke more than a few times and Cooke never once thanked him for it. Cooke actually believed what he was doing (turtling) was a good thing.