Eh, Tyler Bertuzzi wasn't the reason he was stuck on the 4th line all year. Bertuzzi not being here isn't enough on it's own for Robertson's camp to assume that he's going to go from being treated like a 12th/13th forward all year, to top 6 with PP time.
Robbie stayed healthy all year and was 9th in overall PP time among forwards, and 12th in minutes at ES. Despite being 5th in ES P/60 (spending a lot of his time with bottom 6'ers), and 5th in PP P/60 (with all of his time coming on the 2nd unit).
I don't blame him for doing whatever he could to demand a bigger role. I don't think it's true at all that his best opportunity was definitely here just because the coach was fired. Now if the org has told him all along since the Sheldon firing that he's going to get a real shot at earning top 9/6 minutes and regular PP duty, sure, fuck that guy. But if Berube is just now talking to the kid and assuring him of his spot on the roster in early September, it does kind of speak to how the org has been communicating with him.