I dont really think that Kerry said the war was a mistake. I think he was trying to escape that statement - which Bush kept forcing back onto the table. Kerry said that we were mislead about the need for war - and though he voted for it, he thinks we went about it the wrong way. I think Kerry would be in full support, and this wouldnt come up, had Bush done what he promised with regards to planning, etc - which Kerry did repeat a number of times.
I think that the debates are cooled off before they even start. I mean, the candidates cant move from behind the podiums - certain topics are off limits - they cant address the other directly. It sort of takes the debate out of debate. So in essence it pushes for this repeating of rhetoric. And thats what you have to deal with.

I think as far as deathblows, you are right. Nobody really threw a knock out punch. But I do feel that Kerry made much more headway in getting his ideas for policy out there. I dont really feel the Bush did that.