The funny thing about the game is that it is marketed as, and widely understood to be, a character roleplaying game. This is a mistake: it's a skirmish wargame with roleplaying elements stapled on. The rules assume that you will play the game with a battle grid, and many of the powers in fact won't work right without particular attention being paid to the relative positions of figures on such a grid. Furthermore, since everything in the game needs a certain degree of combat functionality, things that would generally be a "roleplaying opportunity" get overlooked. The best example of this is the Warlock class, where you can at creation decide that you character's powers spring from studying hidden secrets of Hell, banned by the god of that realm...for which the game lists no consequences.
A good analogy here is that DnD characters are like Battletech pilots. Sure, they can have complex character development, but the first question somebody is going to ask you is how many tons your mech weighs, and what kind of firepower it's packing.
The other, semi-related debate is whether DnD is copying pages out of WoW's playbook. Here I think the basic answer is no. The streamlining of classes into combat roles simply reflects tendencies and practices that were already in place in DnD, not what had been going on in WoW. Furthermore, the difference in medium and the required elements for play is sufficient enough that it's never going to be a comparable experience, and I'd expect the developers of DnD to realize (and, if they're smart, market the game based on) those differences.
Now, onto the game itself. The game presumes some set world characteristics: it describes in passing things like lost empires for Dragonborn and Tieflings, and the existence of planes like the Feywild and the Elemental Chaos. I find this aggravating because the book never offers an overview of that world, but its characteristics have considerable influence on how the game, especially the various races, are presented. This is especially a problem since the world they describe does not work the same way at a metaphysical level as any DnD world that I know of.
Notes on the races: The reptiles with breasts can die in a fire. Which is a damn shame, because I'd like them except for that one terrible characteristic. As far as Elves go, I wish they had kept it simple by calling them "high"(Eladrin), and "low", which what the difference in character actually is. Tieflings: it stretches my disbelief to the breaking point to consider them a major race. They look like fucking monsters. Humans have had enough difficulty with considering each other tainted by demonic forces, if we were introduced to a people who had an obvious, physical connection? Well, to say the least I don't think we'd be welcoming them into our communities.
The classes are generally good. The biggest thing that irks me about them is how many of them try to set up false dichotomies, something that isn't helped by presenting only two build options. The rogue, for example, asks you to explicitly pick whether you will be a Strength or Charisma type rogue, and certain powers will give you additional benefits depending on your choice. The thing is that while those are both viable ways to create a rogue, they aren't the only viable ways (though by changing skills they did eliminate the Int-based rogues). This isn't to say that the dichotomy is always false: the Rangers' choice between melee and ranged combat is completely legit. Still, there is enough choices to make things interesting on at least the two classes (Fighter and Rogue) that I have done anything more than a completely cursory overview of.
One mechanic that I am highly suspicious of is the "one half your level" modifier, which comes up a lot. It seems like a cop out method of introducing the idea of an increasing general competence. I would have liked to see something more specific. An apt announcement that this is now a wargame comes from the Diplomacy skill, which has the shortest description of any of the skills. Feats, for their part, are better. Toughness is still the worst, because a few bonus hit points is still not worth being able to do something actually useful.
As far as art goes, this edition is heavily inferior to the last. Not every illustration needs to be in all the colors of the rainbow, guys. I especially miss the beautiful pencil sketches from 3rd ed. Also, while I generally enjoy the art of Wayne Reynolds, especially for DnD, the cover is terrible. The pose is too combative, and the fan service is too obvious. Another layout issue that bugs me is that at no point is there actually a guide to the character creation process: not even a handy cheat sheet of the steps to take. This is something I have found highly useful in other games, even as an experienced player. Not including it here was definitely a mistake.
But, all in all, it's alright, and I'm tired of talking about it.