Will said:
The heretical notion occurs to me that it would have been interesting if PCs were designed the same way...
It's not a bad notion from a design perspective and might work for one-off games, but the small power lists would grow dull pretty quickly.
I'm in a Savage Species campaign now, and I have chosen low-ECL base races (a half ogre and a humanoid raven) in order to get class levels quickly. When the game started, several players chose high-ECL races, but all but one have dropped them, in part because you progresss....sooooo....slooowly. (At 10th level, the Ogre Magus (Magi? Mage?) finally is able to do more than one thing a day, though his hit points are such crap that he spends about half of every combat regenerating and unconscious.) 3e changed a lot of expectation about getting Cool New Stuff To Do on a regular basis (how the hell did 1e fighters stand playing to 20th level?), and 4e keeps going in that regard.
As to "h4ter" or not...I'd prefer to state I have always been a skeptical critic.

Barring a massive player rebellion in early June, it's unlikely I will convert my game to 4e or find the game I'm in converted to 4e -- both games are very heavily dependant on later supplements and would need to, at the least, restart from first level as character concepts won't be easily switched. Our campaigns tend to make very heavy use of things not primarily supported in 4e, as well -- cohorts, shapechanging, lots of NPC tag-alongs of various levels and abilities who DO participate in combat and who provide much of the fun and spirit of the game. The PC/NPC line is a lot blurrier in the games I'm in/run, in that there is much less of a KODT attitude towards the "worthless NPCs". Every character has a "family" of allies, enemies, and those who switch back and forth, and these complex interweavng storylines are part of what makes the game memorable. 4e, as currently written, seems to be disinclined to make NPCs important mechanically, and seems to assume that they will all stay safely at home, and not, for example, slip into a character's bag of holding and pop up when they're deep in the wilderness and start doing things like taming dire bear cubs who ALSO end up stuffed in the bag of holding and did I mention jury-rigging traps ala Home Alone to "protect" the cave we were using as a temporary base but not, oh, TELLING us he was doing this so we stumbled right into them when we got back...
Sorry. Digression.
IAE, I'm interested in looking at the 4e design rules to see if you can make mechanically interesting NPCs who are neither combat obstacles nor classed. Getting back to the original concept of my post, I can see statting up all sorts of interesting "defining abilities" for both generic and specific NPCs, but I'm going to need to study the rules in full to see how these kinds of things will interact with actual gameplay. The "party of rootless wanderers" model isn't the only way D&D is played. Indeed, the only idea I've had for a 4e campaign would be a massive city based game, ala Invincible Overlord, but turned up to 11.