Three initial matters.  One, the post is comparing the anti-government rhetoric coming out of Obama's website to something that would come from Karl Rove.  Honestly, if you look at it, it seems an apt comparison.  That doesn't mean they equated Obama with Karl Rove.  By those standards, you just admitted that Obama is a Republican Party operative, because he criticizes Clinton's healthcare with Republican talking points.  I don't think any of us here think such things.

Two, as for what Krugman wrote, the last line in the linked article says, "If Mrs. Clinton gets the Democratic nomination, there is some chance -- nobody knows how big -- that we'll get universal health care in the next administration. If Mr. Obama gets the nomination, it just won't happen."  Krugman didn't say "healthcare won't happen," he said "universal healthcare won't happen."  That's true almost by definition with Obama's plan.

Three, Krugman passionately believes in Universal Healthcare.  I think his criticisms come from that perspective, not from some dislike of Obama.

For your argument, we should separate passability from what is a "better plan."  You make good arguments on passability, within the given context.  I simply disagree on whether the plan itself is better.  I also think it's a strategic mistake to compromise before the sh*t hits the fan.  Ask for a lot, then compromise later.  Honestly, Obama should simply go for the brass ring.  He can negotiate down later, if forced to.

Now, incidentally, I think this is especially tragic because I bet Obama would bring in bigger majorities in both houses of Congress at the top of the ticket.  I also think Obama will do better in terms of leading the nation towards a more liberal / progressive agenda.  I also think Obama is simply better at oratory and communication. It's tragic because I think, if Obama would just embrace mandates, he will have a far better chance of bringing in universal healthcare than Clinton does, due to all of the above.