I've not played 4e, I'm getting a demo this weekend. I like a lot of what I've heard, and threads like this are very informative.
It did make me think of a house rule I'd used in previous editions, and I think it would work fine in the new one. Hit points have always at least in part been described as the ability to turn severe blows into minor ones. That 15th level fighter might have over a hundred hit points, but that doesn't mean you can run him through six times and he just laughs it off. You never get to run him through. That strike just scratches the skin, it bruises him, it beats him back and wears him down. Even if its described as a hit - ie your mace crushing into his shoulder and blood flying - it isn't a serious hit, and looks much worse than it is.
Once you run through his hit points, you've gotten past all that. He has no more immunity to your sword than a level 1 peasant. You can do what you like on a hit. Therefore we had the kill/capture/maim rule. Normally you were striking to kill, and when the enemy was out of hp you'd slay them in an appropriately gruesome manner. If you can do that though, you can do other things. You can maim by putting out an eye, cutting off a hand, shattering a kneecap, whatever you like. This is only done to humiliate an opponent, and to be honest I don't think anyone ever did it. Then there's capture. Rather than running them through, you put your sword to their throat. In 3e terms you have a readied action to attack if they move. This attack automatically hits for a critical. Any creature maimed or captured in this way is considered to be at 0 hp.
This is how I've always looked at hp, so 4e's model doesn't bother me at all. From playing Buffy, my players will already be used to healing surges, as that game has a similar mechanic (I Think I'm Okay).