A national primary loads the dice in favor of the candidate with the most name recognition and money. Having primaries in small states first, lets more obscure candidates a chance to show their stuff and gain momentum, or lose it. I prefer having Iowa and New Hampshire vet candidates on a retail basis first. Granted, in a perfect world, which states got this honor would rotate. But heaven forbid if it should ever be California or New York, which are anomic and media driven, and in the case of New York, the GOP is really more of a phone booth party.
I agree completely. A national primary is a really scary idea. It would complete the centralization of power in this country -- not that it isn't already pretty far gone.