I agree with Ezra Klein's characterization of Jon Huntsman's campaign: "Huntsman has offered the Republican Party a generic conservative platform minus the partisan swagger." And I agree that with Mitt Romney already monopolizing that space within the GOP field, Huntsman's bid was pretty pointless.
But really: what were Huntsman's options? Klein posits (and Andrew Sullivan agrees) that Huntsman's campaign would have been less pointless had he actually taken some policy positions to match his attitudes -- say, supporting the climate platform that John McCain ran on just three years ago. And, yes, there certainly was room for a real moderate conservative dissent candidate within the Republican party. But that's not a campaign for the presidency; that's a campaign to change the party. It's hard to undertake that sort of thing (as a presidential campaign) unless you really are a true believer, which Huntsman perhaps just isn't. The other thing is that while Klein may be right that a dissent candidate might poll better than what Huntsman's doing now, the ceiling would have been low: he would have at best had a Ron Paul type of campaign, with a solid 5-15% and no chance for more, although with some chance of changing the party going forward.
Not that Huntsman has any realistic chance as is. And, really, he almost certainly never had a chance after he accepted the job from Barack Obama. But at least Romney-lite has the plausible-sounding scenario that if something was to happen to the Mittster, perhaps Huntsman could inherit (plausible-sounding, but probably not realistic; Romney does appear to be running about as good of a Romney-like campaign as possible, with opposition just about as weak as possible, and even so he's having quite the hard time consolidating very much support). If he was out there pushing actual policy positions that would draw vetoes from important party groups, he wouldn't have even that.
All of which means that Huntsman basically should not have run for president in this cycle. But if he really wants to be president, then I can't blame him for running the kind of campaign he's running. The real problem is that while presumably there are a fair number of non-crazy conservatives who believe all sorts of non-crazy things and would very much like a non-crazy conservative party to stand for those non-crazy policies, there doesn't seem to be very much of an incentive for anyone to act on it. True believers, again, might do it anyway, but it's pretty rare for something that depends on true believers to actually work out.