As for him wearing it? *shrug* Who cares...
Given that it's issue from AF-1, I guess I don't really. What gets me slightly irritated is when a politician tries to dress to what he doesn't really represent or care about. Bush got hit pretty hard about the flight suit, but he was on a military flight, and as mentioned above, a military pilot, and given his respect for the military, it was something that "fit" him doing, versus say, Obama.
On the other hand, people make fun of Obama and his "mom jeans" and urban dress, but to me, that's kinda what he is and a lifestyle he represents, so it doesn't bug me. Him wearing boots and a cowboy hat to give a talk in Texas would bug me because you know he'd be trying to play to an audience and it's a style of dress he couldn't get away with. The Bushs' and Reagan could.
In the same vein, if one of the Bushs' or Reagan had tried to dress to "fit in" with some urban or enviro-green crowd (whatever form of dress that might be) they'd be overplaying their hand because you know that's not them.
I guess the A-2 just makes it seem like he's trying too hard to fit the Commander in Chief image, which he doesn't seem crazy about, versus the President image. Obama is better off in a suit representing the civilian side of his job. JMO.