I know that my last post sounded a little negative, but since then, I've found that the decisions to just see the head of the dojo as another sempai and to be more self-centered in my training have really been a positive change. The next day, I had a really good conversation with the head of the dojo, and I feel like my relationship with him had suddenly improved. I've also felt an improvement with another sometimes-difficult member of the dojo (a stiff, muscle-bound wrist-cranker who I had a good conversation with a few nights ago), and in general things are improving.
The angry guy hasn't been around much in the past few weeks. I don't know when he'll be back, or how long he'll practice until his next spell of non-training. We'll see how that goes. It's a small enough dojo that not interacting with him is really quite awkward.
I am still thinking about opening another dojo at some point, and this crisis has really focused my thinking about what's important in a dojo.
I'm also still thinking about moving away at some point, for a while, to train at a better dojo.