Hi, tmac. Congrats on your shodan. I'm more than happy to give you my .02$.
Positive energy. I always enjoyed marital arts better under senseis that had that "good coach" vibe rather than the perpetual nitpickers. As a basically untalented guy practicing martial arts, it's really hard to have a day job with a type A boss and then have class under a type A sensei.
Organization. Just having a good, well-thought through plan of what's going to happen for each session, and giving senior ranks some time and space to work out the things they know they need to work on.
Personality Management / Creating a safe environment. Basically this is keeping the wannabe MMA fighters away from the grandmothers who are just in to learn a little self-defense or the 9-5ers like me who want to train and learn something cool, weeding out people who might hurt others and keeping those with injuries or infirmities safe. Just maintaining a safe environment. There's a big difference between YMCA self-defense and American Top Team, so a sensei should match prospective students accordingly.
Guests. The best senseis I've had had close friendships with masters of other disciplines and had them come in for special classes from time to time. It was always great to have that fresh experience, different point of view, etc. and, I think made for more well-rounded students.
Hope any of that helps though, as I read through it, I don't think I'm telling you anything you didn't already know.