I always enjoy this exercise. I think about my favorite ten or so golf courses and feel like there's a specific quality they all have. I've called it different things in the past: ebb and flow, intimacy and grandeur, big and small, uppers and downers, foie gras and cheeseburgers. Cypress may--more than any of my other favorites--demonstrate this quality. Having a variety of setting combining a change in difficulty while keeping a central theme to the course is in my mind, the highest form of golf architecture. I think of places like Ballyneal, Riviera, National, and Friars Head as examples of this concept. Interestingly enough I don't think other stalwarts like Pine Valley, Augusta, or Oakmont demonstrate this quality as well as other lesser ranked courses.
So in identifying the "weakest" hole on courses with such disparate physical settings, hole shapes, and shot requirements, I think it helps to ask about purpose. First, figure out what you think is the hole of least interest or quality and then ask what it's purpose is. At Cypress Point, I think your answer of #10 is pretty astute. It is a bit mundane for the reasons you state. After three holes of pretty intense decision making with small targets and bad consequences for a miss, 10 is a hole that lets off the gas, opens your world up a bit compared to 7-9, and allows a breath before the run to the ocean. But in its capacity as a hole that goes back uphill away from the ocean, allows the routing to get to a full 18, and also allows a reprieve for the players, it's a great hole.
So is 10 the least interesting or exciting hole on potentially the worlds greatest course? Maybe. But does the golf hole serve a purpose and accomplish its purpose well? I think yes. Which is to say that it may be lesser hole compared to others, but it works beautifully.