Of course, the Liberal Party had the rough equivalent of a national primary last time around, and not only did it produce more interesting politics, it turned the underdog candidate in to the leader of the opposition.
Why I like the de facto national primary
There's some level of nostalgia over the notion of a long, drawn out primary process in which Iowa and New Hampshire kick things off. This is supposed to help the Jimmy Carter-type underdogs "build momentum" and give voters a chance to "deliberate" over their decisions.
In reality, of course, we had a system in which two non-representative states (IA and NH) decided our nominee last time, and they were gunning for the same "right" this time around.
Underdogs are favoured when the front-runners are divisive, regardless of the political structure. This year, Hillary/Barack threatens to be divisive and nasty -- especially with the Clinton team trying to muddy the waters on her Iraq vote -- so we'll have to see if Edwards can capitalize on that.