this is not a journal title

From all the second hand sorts of analysis I've skimmed, I suspect the answer to (2) is that he/his handlers feared that being his usual self would lead to cries of "mean! sexist! jerk!" and the like. There were fears that he might be seen as condescending if he went after Palin the way he has gone after other people. I get the feeling he may be something of a loose cannon and prone to saying some pretty wild things, and so even if his opponent were more of an equal, he may have wanted to restrain himself a bit so as to avoid any remarks that he'd get attacked for in the press.

I haven't had a chance yet to track down, let alone watch, any of his previous speeches, alas.