Thanks to everyone for the informative replies to my original post -- I certainly learned a lot. That said, AA could have communicated better what was going on and made decisions about how to unload fuel more quickly, rather than leaving us sitting out on the tarmac for almost an hour with no a/c.

And as if too prove that there is a weird karma in the universe, my ORD-DCA flight last night had to return to the gate to add fuel when ATC gave us a revised routing.

Dave