I'm sorry.
i think you are reading too deep into what the polls mean. yes, they are a reflection of a greater dis-satisfaction with the administration. But I think you give far too much credit to the "pollees" if you think these polls are their way of saying "well this is what the president darn well better fix if he wants my support."
people don't give politicians that kind of credit. They chew them up and spit them out (often with good reason). If somebody said "yeah, I would probably have voted for Kerry in retrospect," than they probably mean it.
Of course this is rather arbitrary. I think it's interesting where publc sentiment has gone in a year. I actually believe that had the election been this November, yeah Kerry may have won, but the overall turnout would be smaller. It's just interesting what a crappy year can do to people.