Because "2 hp" already has an established meaning in my mind, and I don't see any virtue in changing it for this purpose. I can easily play a game that works very well in which "2 hp" means what I think it means. There's no need to change that interpretation, and no benefit to me for doing so.
2 hp is "nearly dead"?? I don't see how this can stand up; a magic user starts with 2 hp total - is he slowed down by the heart-lung machine he has to adventure with?? The only hp values with any real meaning in D&D are zero (which has always been there - you are dead, incapacitated or dying) and half-hp (bloodied; came in with 4E but I hear hardly a whisper against it).
Healing surges are a way for people who don't want to think about strategy alive, as in operational parameters. Its not so much, 'how do we fight this encounter?' as ' do we fight this encounter?'
I think you have misidentified your target; this effect does exist in 4E (as well as all previous editions, for a specific approach to play), but it has nothing to do with healing surges.
It has to do with Extended Rests - or, more specifically, the
recovery of healing surges. Because this is tied to game-world ephemerae rather than system functions, there are only two options: (1) the DM designs to limit rests via fiat plus excuses (excuses optional, strictly speaking), or (2) the "resources" of healing surges and daily powers lose all relevance as they can be recharged arbitrarily.
Having healing surges purely decouples the recovery capacity between encounters from the number of clerics in the party. This I regard as no bad thing.
Making surges (or any type of healing capacity, for that matter) a resource limited only by the game-world conceit of time passing is a major system flaw that has been present since the earliest editions. Kludge "cures", such as expensive healing potions, heavy potions (and heavy money!) with limited carrying capacity and so on have been tried from time to time. But the core problem has never been addressed.
The answer seems to me to ba a mite tricky. Standardising adventure design (so that X amount of "adventure" must be tackled before a long rest or that adventure "stage" is failed and the rewards from it lost, for example) might be one way. Relating the amount of resource recovered to the amount spent before resting might be another - or relating it to the XP earned since the last rest.
Just saying that resource recovery takes more game time, though, is pointless. "Game time" is meaningless in the real world - it gains relevance only via DM fiat - which is the most tedious and dysfunctional "system" I can imagine.
Simple way to houserule a fix here: someone who goes below 0 h.p. cannot be cured above 10% of their total until some time (an hour or two) has passed, except by heavy-duty cures e.g. Heal.
Ding! This has ocurred to me, too. To make a "realistic" (ha, ha - as realistic as D&D has ever been, at any rate) game of 4E all you need to do is declare that a character at zero or less hit points cannot
spend healing surges. Only surgeless healing magic or potions will help. Job done.