Wanted to throw this out there to see what the experts had to say. In my mind there seems to be a case to be made that Koko could be a more valuable assett for the B's to hang on to than Spooner.
From what I have read, it seems like they are comperable talents --- smallish, but offensively gifted forwards who put up a lot of points in juniors and are about ppg in the AHL. Even the knock on them is the same -- defense. The main difference is that Spooner seems to only be fit for center, while Koko can score a little more and play the wing.
I, like many others on here was rooting for Spooner to take Kelly's place as third line center, but I'm not so sure about that anymore. The more I see Soderberg play center, the more I want him to stay there. Since the top two center spots on this team are locked in, Spooner would be third line no matter what, however I think Soderberg fits that role better because his size allows him to play a grittier game more fit for thrid line duties.
While Spooner coing up to the B's next year means that Soderberg will be underutilized (much better center than he is a wing). Koko on the other hand seems like a similarly high end prospect that could fit in at the wing where the Bruins need the help.
If one of them (Spooner or Koko) is going to be used in a trade package, I'm inclined to think the that Spooner has more trade value, and is fighting a tough uphill battle to break in as the top 6 center his talent projects him to be while Koko could fit in nicely as a third line wing to break into the NHL next year.