I think that this is a very honest evaluation of why Bush flubs phrases. And, while I don't think that he "stutters", I'm sure that many people would seize up altogether if they were standing in front of that many people. They say that the #1 is public speaking and as someone who makes many presenations to smaller groups of people (usually no more than 10), I will admit there are times when I'm nervous and have forgotten to make a point. One can only imagine the pressure involved in these events.
Then, I look at circumstances like the President's Joint Address on September 20, 2001. Knowing the message of strength the President brought to a grieving nation that night and the power with which he delivered it, it makes me understand the depth and scope of the President's job and reinforces the appreciation I have for George Bush.
Heck, even looks like some people in California get that too.
Shades of VietNam