And honestly, if you like to play 4e as one enormous combat encounter after another, as I understand many do, that's perfectly fine. I've played Descent for hours at a time, after all, and it's perfectly fun. Speaking of which, let me plug for that real quick.
This ought to look familiar. It's a tactical miniatures game that has dungeon tiles, pre-defined treasure, and pre-defined characters with the option of creating your own via an elaborate system of points and balances. It has a mechanic for defining exactly how evil the Overlord (DM surrogate) can be to you, via a system of threat tokens and an Overlord deck containing threats and hazards like traps or a surprise spawn of monsters.
The boards are pre-defined, so you build it as the players come across it. They work together to clear the dungeon and grab treasure as fast as possible, so that the Overlord doesn't have a chance to summon hordes of monsters to wear the heroes down. Occasionally, the adventure will call for a big baddie, like a Demon, Giant, or Dragon, and those can take a couple of hits and some interesting tactical maneuvering for the players to overcome. There's even a campaign mode, in the form of a purchasable expansion. Its been described as a tabletop game of Diablo, taking two hours+ to go from scrublike beginning to demigod-like end. Played right, with a mind towards cutting time, it's a blast and a half, where everybody's running across the dungeon and strategizing and cooperating, but played with a bad Overlord, it's a boring, slow grindfest where you're cutting down enemies meaninglessly over the entire game.
The important point to note, in my opinion, is that except for the parts about threat, this game sounds exactly like 4e. Which is funny, because nobody tries to tell other people that Descent is still a roleplaying game, or that you can roleplay out the reactions of your hero to the new kobold or that the magic sword you picked up decides to talk to you. It's dungeon crawling reduced to its most basic form, that of: Kill the Monsters, Take Their Stuff, Kill More Monsters. It's literally all the rules deal with, and that's ok. And that's hard for some people to grasp!
Some people, again, will get upset when you tell them that their game isn't the same as games before it, or that their game is just a little battle simulation, but really, that's just fine. Just quit pretending that your game is the same as other games, and we'll be good. If you choose to play Monopoly, or Risk, don't try and tell people that it's the same game as Runequest or Shadowrun or hell, even GURPS. You're not playing the same game, or the same type of game. There's nothing wrong with your game. Really. You can have a game where the entire world is designed around combat balance and everybody has magic items that only work thrice a day and abilities that you can only cast once until you get in another encounter when you can cast it again, or a sword swing you can only use once a day because damn it, how did it go again? But if you're going to be playing a game where the mechanics in no way allow you to A) easily make up new ones or B) emulate any sort of literature, fiction, movie, or real world occurance, then you're not playing the same game as me.
AND THAT'S FINE. So quit getting butthurt when people tell you that "4e ain't D&D." It's not, and that's perfectly fucking fine. Neither is Descent, but you don't see its fans getting up in arms about it. Look at it this way, and this is the best way I can think of to describe it: You have a computer. You decide one day to build another computer, using almost entirely different parts but retaining the same rough style of the case. You then decide that your old computer is your new computer, because they're both in grey cases and both of them are in rectangular cases and both of them do roughly the same thing, so there's really no difference and you'd have to be some sort of zealot to think so.
Most people would call you crazy, right?