I suppose this brings up a valid point of 4e:
The game is so tightly focused that every character must know exactly how his character functions in order for the game to work properly.
Correct.
4e is often derided as "rules first, fictin second". I think that is unfair - as if the fiction didn't matter!
But what is true is that 4e relies utterly on mechanical resolution to drive the fiction. You can't just potter along in the shared fiction and assume that the mechanics will take care of themselves (this is one of the ways in which I think 4e resembles some tightly-designed indie games).
So your players who don't know, and aren't bothering to learn, their PCs are certainly not playing the game as it is designed to be played!
As far as I can surmise, damage values in 4e assume that characters will be burning healing surges and falling unconscious in combat. If the players aren't prepared to deal with this--either by not understanding how their characters work or refusing to work as a team--that the game sort of falls apart without them.
Absolutely. Actually, with good play and management of healing you can often avoid the "falling unconcsious" bit - by preempting it via healing, and therefore not suffering the action economy downside. But if the players don't have any conception of how they're going to handle this, the game will break.
For the first year or so of my campaign there was no leader in the party, and the PCs focused on bringing their own healing resources - eg the fighter was a dwarf with second wind as a minor, Comeback Strike, and warlord multi-class. Since then the ranger PC was rebuilt as a hybrid ranger-cleric, and the paladin's wisdom has increased to the point where he has 4x/day rather than 2x/day Lay on Hands, and healing has become more about party play than individual play. But it is definitely something that the party has to be able to do. If you can't unlock surges during combat, you will suffer!
In some ways, this is a boon, as it creates a game that works exactly as intended, but, in some ways, this is negative, as it creates a game that can be disrupted if players aren't playing according to the game's expectations.
Because I play with players some of whom are rules geeks, and all of whom are happy to learn and work with the rules, for me it is a boon.
For those who like a more "coast along in the fiction letting the mechanics take care of themselves" vibe - and 2nd ed AD&D in particular was often played like this, in my experience at least - I think it reduces the viability of the game.
EDIT to add: What B.T. is reporting here might give a better sense of what some 4e players are dissapointed about in D&Dnext so far - it doesn't seem to have that same "tightness" of mechanics, and the way those mechanics are designed to push and be pushed hard as the core of what it is to play the game.