Then by your own admission, 4e does not have a fifteen minute workday, as your number of healing surges has nothing to do with your level of strength, nor do they allow for any sort of nova. A fighter with one surge and a fighter with ten surges fight the same. A wizard with one level 9 spell slot and a wizard with ten do not fight the same.
Sorry, but that doesn't logically follow.
In AD&D 1e, a 10th level fighter with 100 hp, and the same fellow with 1 hp, both hit with the same frequency, and both do the same damage, but they are not the same. Nor, to be quite honest, do they fight the same, for it is unlikely (at best) that the player will make the same choices in each of these instances.
A fighter with 10 surges can afford to be reckless. A fighter with 0 surges cannot.
If the fighter's player knows that his DM is likely to be taking his healing surges into account when planning encounters, then he has a rational reason to face each encounter with as many healing surges as possible. Indeed, this can become a vicious spiral:
(1) DM creates tough encounter that the fighter barely has enough surges left to survive through.
(2) Fighter begins trying to maintain more surges; has more extended rests.
(3) This makes other encounters too easy (according to the DM), so he dials them up to 11.
(4) This makes the fighter more prone to want full surges before encounters.
etc.
EDIT: If it helps, I will agree without reservation that the 15-minute adventuring day need be no more a part of 4e play than of 3e. And I believe that it need be no part of 3e play, at all.
RC