Yeah, I gotta go with Klaus here. The issue, at least as I see it, is that KM, you don't think that healing should be tied in any way to the healed. Pre-4e this was true. You could be healed infinitely.
But, for me, the issue isn't really agency. The pre-4e character had no agency over his HP whatsoever. All of his healing was at the mercy of other characters (excluding, of course, characters who could actually directly heal themselves

).
With surge mechanics, you get to heal yourself. But, to limit the amount of action you could do in a day, to simulate actually getting tired/exhausted/whatnot, we put a cap on the number of healing surges a character has per day.
Granted, you can die with healing surges left. But, again, is that really problematic? Your character just didn't reach deeply enough and he died. Mostly healthy people have died all the time, barring whatever it was that killed them. Some people die from fairly insignificant wounds - a rapier stab to the heart will kill someone, despite the victim being otherwise pretty much untouched.
Your character shouldn't need to be completely disassembled to be killed. There are sort of kludgy workarounds for this like Coup de Grace rules, but, typically those are so difficult to actually set up in game that they rarely come up. Trying to kill that guard before he raises the alarm, when you have to get through all his HP, is very, very problematic, unless the guard has less than 5 hp.
OTOH, with surge mechanics, you can whack that guard even though you haven't actually eaten through all his actual hit points.