I can personally confirm two of your personas’ problems with D3, since I work as both a designer and an analyst. My tools are R and SQL on one hand, and Adobe Illustrator on the other. I have done a fair bit of hobby programming, and coded a lot of HTML/CSS back when that was all websites required.

Conceptually, D3 seems an awesome extension on how pages are built — but useful conceptually to people who alreadt think about that, i.e. developers. I have other tools and trends to keep up with; do I really want to become a web developer as well? And having absorbed certain sensibilities from real (old-school) programmers, I cannot bring myself to like JS code, or summon the desire to learn it. So I lean towards getting back into Python and its visual libraries instead.

On the other hand, when I’m in designer mode (after analyses and internal only viz work), I want to think about pretty high-level stuff. I don’t really want to worry about the details of how things are drawn.