I think that the move to climate change is largely in recognition that man can affect climate in a variety of ways, not just temperature (for example, precipitation amount and form, etc.)
As for Gore, I don't spend a lot of time thinking about him. I'm not a huge fan, but I also don't hate him. I think that he does fit the mold of an alarmist more than an educator, which I have a problem with. But, I try not to get too personal about it.
Your last points are quite valid. There are uncertainties in the temperature predictions, and policy makers are being asked to make tough economic decisions in the face of this uncertainty. I am much less certain about the way to approach the AGW issue as a matter of policy than I am that the science has a reasonably strong foundation. The issue of unilateral vs. international efforts that you raise is an important one, and I agree.
The US alone won't fix the problem....but China would also never be the first to act considering they are still trying to develop and the legacy CO2 is primarily ours and western-Europe's. That doesn't change the fact that china has to come on-board sooner than later, but if we assumed for a moment that it was obvious that AGW is real and we had to act, it raises very interesting diplomatic questions on how to bring all nations on board trying to curb it.
I feel a lot more comfortable sticking to the science, but the policy is a bit more intriguing!