Denver lost Bozak early, so that's at least a wash with Stoa leaving early. Bozak stayed a year longer than some had expected, but most Gopher fans are pretty glad he was ready for the next level.
Rakhshani turned down a very good offer from the Islanders to stay and be the Denver captain this year as a senior. As a fourth round pick, he's a not a sure-fire NHL prospect, but has developed very well as a middle rounder into a fine college player and leader, with a decent shot at the pro level. Had he been a first or second rounder, I think the pressure on him would have been greater to jump. But he's a great student, loves the school and knew he'd be captain with a pretty well stocked supporting cast. His descision to stay was crucial.
Ruegsegger has been really hampered by injuries in his career, and while he once was a serious NHL prospect, I think he's more likely headed for law school than an NHL career. He gives every ounce of effort he has for Denver, but his skating skills remain suspect to be playing beyond the AHL. There was no pressure on him to jump as a sixth round pick.