As for the class, like most classes, it depends 100% on the instructor. There isn't anything in the academics you couldn't read for yourself in the books or forums in an hour. But, if you get an instructor that is really a photographer you can learn a lot - probably much more from the informal q&a than the class, per se. On the other hand, if this is just another specialty class and the instructor isn't really a photographer, then you'd be better off spending the money on gear and the time on reading.
In addition to this site, check out the Wetpixel forums. Good stuff there too.
You're right to want to concentrate on dive skills and comfort, of course. But, don't assume you have to achieve Zen perfection before proceeding. As long as you can remain "in the dive" (situationally aware and in control), stay off the reef and be a responsible buddy, have at it. Buoyancy will continue to improve - probably even faster because you'll be concentrating on it.
In addition to this site, check out the Wetpixel forums. Good stuff there too.
You're right to want to concentrate on dive skills and comfort, of course. But, don't assume you have to achieve Zen perfection before proceeding. As long as you can remain "in the dive" (situationally aware and in control), stay off the reef and be a responsible buddy, have at it. Buoyancy will continue to improve - probably even faster because you'll be concentrating on it.