I'm less concerned about the length or par, or degree of difficulty or ease. I want the hole to set the tone for the day. It should give you an idea of the course's identity. I want it to express themes that will be emblematic of the day. (You don't get a second chance to make a first impression.) The first hole can give you an big indications of those questions: what type of course is this going to be?; what type of attention to detail went into this?; do the bunkers look artful?; will the greens have some flow? were creative people involved in the creation of it? etc.
I like Yale for that reason. Hole one gives you an idea of what you're in for: big greens, contours, pits, large scale, elevation. So does the first at WF West: it says get ready for battle.