I've taken Barry's questions out of order, for the record, so that's why he's saying hello in his second question.
If Kostin purposely avoid playing Berube's style in order to be traded, that would be one very cocky move, because that's not a great way to make another team want to acquire you. And it's not certain yet that Kostin will actually be with Edmonton. For the moment, he's in Bakersfield while they get his visa situation sorted out.
I've certainly had people tell me over the years that Kostin would be a great power forward on a top line but even then, it was clear that his role on that line would be to win battles in corners for loose pucks and get the puck to people who could score. Kostin has never in the NHL shown himself as a guy with a great shot or someone who could generate a lot of offense with his playmaking.
Berube has said it a bunch of times: they want to see consistency from Kostin, to know what they will get from him on the ice. They never felt they were getting that. And once a player has to go through waivers, it's usually in a team's best interest to trade him for something rather than risk losing him for something. Maybe Kostin finds a home in Edmonton. The Oilers got him cheaply enough, trading a defenseman who was in pretty much the same situation as Kostin.