I agree with Princeton Fan's comment. Having known several players at each of the Ivys, I also know of several players who were attracted to Princeton specifically because Kampersal's personality was a big draw for them. And I haven't heard the big negatives associated with some others.
Like any coach, I am sure he has his strengths and weaknesses, but many players no doubt find a more laidback style like his much more appealing than a more intense one.
Believe it or not, most players probably don't choose which school to attend based on how far their team will go in playoffs every year. The fact that they are consistently a top half-ish team, he doesn't overrecruit, everyone gets playing time, the coach is likeable, and the Princeton campus is stunning and secluded, yet easily accessible to the city are all factors that likely carry FAR more weight with most recruits in their decision-making.
And as suggested by the rate of player attrition from Princeton relative to other ECAC schools over the past 5 years (posted in the Brown thread last season), Princeton actually has one of the lowest rates of players leaving the hockey program prior to graduation. That must say something positive about their experience.
Yes, there are other coaches with better records of playoff success. For those for whom that is a key selection criteria, they will choose go to those programs. However, I also know for a fact, that despite their more enviable program successes and playoff records, the coaches were also a turnoff for many potential recruits for other reasons.
While the grass may look greener on the other side, you don't know how much weed killer they used to make it appear that way.