If Bush had come along at a time of relative global simplicity, I think history's evaluation of his presidency would be far different. Precisely because he was, as you say, an "unapologetic plain vanilla pro American moderate republican who didn't like partisan bickering and put his foot in his mouth at the worst possible moment," he was sorely unequipped to deal with the realities of complex global reality. Negotiating with the rogue states, emerging superpowers -- that's to say, states and head-of-states with suddenly big egos -- requires much more than a "likable" man who also happened to be a rigid ideologue.
I find your defense of Bush's fibs regarding the WMD particularly troubling. In doing so, you're making excuses for Bush and holding him to a lenient standard -- which is what you're asking us not to do for Obama. I am actually less inclined to condemn the fact that the Bush administration lied than the fact that it lied to mire us in a war that was a waged for the sake of Bush's ideology, which you seem to support, but which I'm not nearly as inclined to. The US is no longer quite the T. Rex it used to be; the rest of the world is filling up the vacuum left by the USSR. A lot of sound and fury will get us less far than crafty, manipulative, subtle, intelligent diplomacy. I'm hoping Obama can supply some of that. It seems counterintuitive to practice diplomacy with terrorists, but terrorists are also individuals capable of speech and choice and logic -- albeit very, very warped logic. Sometimes softness -- yin -- is preferrable to hardness -- yang.
Judging Bush is different from judging the Bush administration. To Bush's credit, I think he went into office with nothing but the best intentions. But good intentions pave the road to hell. Katrina, the miring of the Iraq war, and the economic crisis are what history books are going to write about the Bush administration, and that's going to haunt Bush's personal legacy. The poor guy tried his best, yes, but he in the wrong place at the wrong time.