I see, and oddly enough agree with, both sides of this.
For myself, I too definitely hope for a "Berserker" theme (now going to be "Specialty" apparently.

bleh) and a "Barbarian" background. It just makes more sense, to me...and always has, in my games, been the case. I've even gone so far as to keep "barbarians" restricted to a certain human tribal culture in my game world.
At the same time, the "Barbarian" as a D&D class has a longstanding tradition and great popularity (as far as I can tell). And the core mechanic/niche of the class, for D&D, was always the rager-guy. So, from a standpoint of "if it ain't broke" and/or not changing things for the sake of change (that kinda thing just makes me nuts!) I also agree with ComradeGnull and others that changing it, while it would be more accurate and (I think) flavorful, is unnecessary. I'll still define my game world's "barbarians" as I always have, a specific, yes often "wild" and "more primitive" culture than the cities and castles of the more "civilized" realms.
But, I will still hope that we don't see "Barbarian" as a class, but Berserker as a theme (preferably limited to Fighters, but in the interests of people's versatility and imagination, I'll take it allowed for any class). I just doubt the likelihood that will happen.
Warlord falls into this line of thinking also...easily doable by a theme/specialty tacked onto a base class (why not a cleric warlord? or hells, a mage?). The Cavalier and/or Knight, also. I just don't think every permutation of the Fighter needs to have its own class if it can be done via background and/or theme.
Now, of course, that calls up the whole 'Then where do you draw the line?" debate. i.e. If yer gonna do that, why can't Rangers just be fighters with a "Woodsman or Hunter" background and an "Archer or Two-Weapon Fighter" theme? Why isn't a Paladin just a Fighter with a "noble/knight" background and a "Holy Smiter or Devout Champion [or what have you]" theme?
There's really no right/wrong answer/place for that line, of course...I base mine on traditionalism, I suppose...and my perceptions of the popularity and legacy of certain classes. Rangers and Paladins just came first...they have a slew of special abilities that are their own...even though Barbarian and Cavalier both made their entry shortly thereafter (in 1e Unearthed Arcana) and had all of their own special bells and whistles...they seemed forced...pulled out of stuff that I could reasonably envision ANY fighter (with appropriate backgrounds) being able to do.
And, in yon early days, saw more than my share of "knight or "barbarian" characters who were just Fighters with different clothes (or lack thereof) and weapons. The window dressing was different, the role play certainly was different, but the character sheet still said Fighter.
Warlords, of course, are the new kids on the block, so they don't get many "traditional" points. I also feel their range of special/class abilities all [or mostly] belong to any Fighter character...the guy who fights better than anything else! A warlord, by definition, is all about fighting..."scream healing" mechanic aside...but one could make the argument that aids in the group's overall ability to Fight, so it still counts in a way. Better than the fighter, though? No thanks. Theme, please.
Just my thoughts.
--Steel "berserking over my barbarians" Dragons