Interesting. Lately I have been thinking of the kote as, actually, the forearm. I guess I have been seeing kotegaeshi as an elbow manipulation this whole time. When people go for the wrist itself it is like, it may hurt, but it never really seems to get use's balance unless you are moving the elbow around too.
Now this gets interesting. The Kote as explained to me has included the region from the center of the palm and includes the forearm (but not the elbow). In kendo the Kote is the glove which covers that region. Kote is not just the wrist and a strike to the Kote is to the region covered by the Kote.
I think an applied kotegeishi will affect the wrist first followed by the elbow followed by the shoulder and so on. This speaks again to the points raised by Janet and Katherine - where the true power comes from body movement and placement. I guess what we are talking about is where the energy transfer begins.