About the "Warhammer Fantasy RPG" comparison... it's interesting that Warhammer, the miniatures game, got spun off into a VERY down-to-earth and realistic low-fantasy "anyone may die any minute" RPG, whereas D&D, which was originally a sort of realistic and gritty game in its own way, is now becoming more of... a miniatures game! :/ (Of course, D&D was originally a miniatures game too, but....) I like "Warhammer Fantasy RPG" and I like D&D too. And naturally since I like D&D I want the world's most popular RPG to have all the features that *I* like, rather than just switching to another, less popular game. ^_^
I think one of the main developments that may be happening with D&D4E is that they are (possibly?) removing the "mook" stage of character development. In most non-level-based RPGs (like Shadowrun, the White Wolf games, etc.), you start out and it's immediately assumed that you're better than the average person. You're already a hero, and then after that, your improvement is only gradual. But in D&D, you start out at first level, and you GRADDDUAALLLY improve until, at a certain point, you are totally awesome. (And the monsters you face are totally awesome too... but if the DM wants to, they can always remind you of your awesomeness by giving you the opportunity to fry a bunch of surly orcs who mistake you for a first level party.) In older editions of D&D, this was even more the case... you might start out with a character with awful statistics and roll 1 for your hit points and then it's pretty much assumed that you will die quickly. I mean, have you read those old OD&D modules with all their instant death?! They're insane!

Enjoyable if you have the right sadomasochistic mindset. Only the best and luckiest people would survive to high level... like they say over and over in 300... "ONLY THE HARD! ONLY THE STRONG!"
3rd edition D&D, compared to previous editions, already goes a long way in making your characters more "heroic" from the get-go... minimum stats and max HP at first level and all that which makes life liveable. But at the same time you *are*, in an essential way, "just" a first-level character, and you are sort of equivalent to all those first-level warrior goblins and orcs and whatnot... following the "realistic simulation" model as if you, a first-level fighter, are somehow equal to a first-level commoner NPC. In 3rd edition D&D, and all older editions, you ARE a mook when you start out. You may *become* a hero when you get to high level, but first you must endure mookhood, where you may, just may, be able to beat a bugbear.
Personally? I like this style of play. I like the "start small and get big" element. I can see why other people wouldn't like it, but I do think it is a defining element of D&D in a way. Of course D&D is always going to have levels, so you will always have the element of getting stronger and stronger as the game goes on. But I do like it when the baseline, starting level of play is fairly low. Then you can have the Shonen Jump progression where your characters get more and more bad-ass and you really feel that you earned it.
However, in the defense of D&D's apparent move towards a more "heroic" scale of play, I guess you could say that most other, non-D&D RPGs already feature "heroic" characters from the get-go. And in those other RPGs, people certainly enjoy and "earn" every single level of XP or Skill Point that they acquire.
My feelings are that D&D4E may or may not be a good game. It definitely will represent a big break from the "traditions of D&D", though, as opposed to D&D3E which was more of an evolution. D&D4E may be a good game, but it will be a very different game from old D&D, I'm thinking. For better or worse.
Jason