I'm curious...what is it with all the "Brooks is insane/weird/eccentric" stuff?
What exactly did he do? Are we talking about Charlie Sheen, Tom Cruise, or Joaquin Phoenix levels of weirdness here?
On a personal note, I met/saw/took pictures/listened to him at the ST Vegas Con in 2010.
It was a revealing experience for me as I know can see where those "querks" come from.
Of the discriptors you listed, I think eccentric applies to Arvery more accurately than the others.
I was listening to him on stage answering questions from the fans and I say thinking to myself... "I have no idea what this guy just said/means"
You can also get a good feel for Avery in Shatner's "The Captains".
The guy is "out there".
In my opinion, he's a much better musician than actor.
I kept rooting for him watch DS9. I complelety supported Star Trek having a "black captain". I thought it was appropriate and the franchise needed to go there. (Same with Janeway). But my thoughts were always "why didn't they chose someone that could act?"
As I said before, the plethora of great supporting actors helped him immensely. Being the CO of a Space Station rather than a Star Ship where stories could be centered on other characters and situations "hid" is limitations as an actor.