Well, Don, that first knife is mine, so I can tell you first hand that it is very comfortable. When I first saw it I was also struck by the taper, but to tell you the truth, I have never really noticed it when cutting. Dave was going to do metal (or mokume) bolsters at first but that didn't work out, so on his first knives he went to a micarta bolster instead. I imagine working with that medium versus metal changed how he made the taper (at least in the beginning). But he could answer that better than I.
As for handles. I like wa in general, but it isn't that simple. I like Devin's squashed octagon handles but also like Del's modified full-tang wa handles. With that said, D-shaped are my real favorite. I'm not sure why. I have two and the way that they fit my hand is perfect. Western handles I love but as far as feel while cutting, they are my least favorite. With that said, I have some amazing rehandled knives and I love them no matter what I think about handle style and feel.
k.