Thanks to everyone for their answers. Before posting this as a topic I thought about what title I'd choose and I chose "What does Pacific Dunes lack?" instead of "What are Pacific Dunes' weaknesses?" because I wanted the world's best courses to be included in the discussion. But I didn't choose "What Do the World's Best Have that Pacific Dunes Doesn't?" because the world's best are so diverse that there isn't a discrete set of traits that they have that PD doesn't.
Basically, I had just played a course that was such a complete experience I found myself saying, "If the consensus is that there are 25-30 courses in the world better than Pacific Dunes, then I'd sure like to know what else these rankers think Pacific Dunes would have to do to be considered among the very best."
I've read some very good answers here and I appreciate everyone chiming in. I sure don't think the course lacks anything, but in a discussion group like this I think it can be instructive to take the opposite stance and see what comes out of it.