I don't agree that he's been "posturing" in an unrealistic way. He's said throughout that he's not perfect, that he makes mistakes and that he'll continue to make mistakes. But there are some core things he wants to do, and I think he's done them well overall.
If he's "coaxing controversy" out of something actually policy-based, or something Hillary actually said or did that his campaign thinks should get more scrutiny, I think that's justified and even necessary. (
This report indicates that while Hillary got more media scrutiny and criticism when she was the front-runner, that balance shifted in the other direction starting in about February.)
He stayed well away from many, many Rovian lines of attack that could have been used and would have been used against Hillary had she become the Democratic nominee. Had he used them, he may well have wrapped this up much earlier. But he didn't, because it's not the kind of politics he wants to engage in.
If you broaden the definition of "gotcha" politics too much it becomes meaningless. If Hillary says that she supports driver's licenses for illegal immigrants and then says well not exactly, is pointing out that contradiction "gotcha" politics? That's not what I think Obama means.
I'm trying to think of what you have in mind re: McCain's lines of attack. Public financing? I have mixed feelings about that. I think it's a nice idea, but I don't know if Obama can afford to turn up his nose at the unprecedented fund-raising apparatus he's assembled. And if it's 1.5 million donors, 90% of them [I think, haven't found a source in a quick search though] contributing less than $200 each, it serves the same basic purpose -- severing the strings, not being beholden to big-money contributors.
Examples would help.