I agree with you that the B's brass shows favoritism, but I'm not sure it's a college thing. Carlo came from juniors, he skipped the line. Gryz went to college but spent time in the AHL. Lauzon and Vaak are not college players but they saw time ahead of Sherman who played with Donato at Harvard. I think most of those choices (Sensyshyn included) have been about readiness and player development. Legit, earn your spot situations.
My fear is that they favor legacies (Donato, DeBrusk) but I want to believe it just looks that way, and the truth is that they favor the kids they think have the biggest upside. So guys like DeBrusk and Bjork were given spots ahead of Heinen and Cehlarik because they think they'll be better NHL'ers, even though DeBrusk was outplayed in camp by both of those guys last year and Donato was outplayed by Cehlarik this year).
Their treatment of Cehlarik in particular, confounds me. He's big and smart and defensively responsible. He's had two good camps and was the best rookie in camp, by far. He's scoring at a good clip and has 6 points in his last 6 games, yet he can't get a sniff of NHL time on a team ravaged with injuries.