Onion article: a few months old, still sadly true in my opinion.
I don't see any of the major candidates as "serious", excluding Huntsman, whose relative moderation leaves him low in the polls and, as a result, out of debates. I think the fact that Newt Gingrich is the front-runner in a party that claims to fight partly for social conservatism is a hypocritical disgrace. I think the whole revolving door front-runner phenomenon is an effort to get anyone but Romney into the general election, because he's seen as bland, or somehow, too liberal.
That said, OP said that these primaries are important. Well, they certainly should be, but I don't see the Republican politicians taking it that way. At least until recently, when a small shred of seriousness revealed itself when most of them bowed out of the debate Donald Trump was going to moderate. But from the endless, repetitive debates, to the utterly stupid, hypocritical, or untrue things they are caught saying, I think a lot of people here in the USA and around the world see this as some kind of circus. But for the most part it looks like the GOP is planning on throwing the general election so their party doesn't take the backlash for any failures (Republican obstruction-generated or otherwise), particularly economic ones, that Obama might suffer in his second term.
P.S. I didn't include Ron Paul in anything I said above. If he actually believes in the things he says, how he's in the Republican Party is beyond me. He should be running as a Libertarian. If he actually cared about the ideology he talks about, he wouldn't be worried about the disadvantages that come from running as a minor party candidate (which, to his credit, he has apparently wanted to fix). But his views aren't in line with today's GOP at all.