It was mentioned a few posts earlier that raising AC to make dodging more realistic instead of using "missed me" HP would not bog down the combat. This is true, but I'll tell you right now that it would make it damn boring. I don't care how much suspense there is in knowing who gets the first (and probably the most telling) blow, if your high-level fighter never hits, you get bored.
And why would your high-level Fighter never hit? What, is there no continuum between always hitting and never hitting?
As I said in a previous discussion:
Right now, a 10th-level Fighter (79 hp) facing a Fire Giant can take about four shots (averaging 24 hp). Facing another 10th-level Fighter armed with a mundane bastard sword, he can take eight blows (1d10+5, averaging 10.5); versus a +1 sword he can take seven (1d10+6, averaging 11.5). Against a horde of 1st-level Warriors with spears, he can take countless hits -- 18 supposedly good shots (averaging 4.5).
If we halved the Fighter's Hit Points, he'd still be able to take two good shots from a 12-foot giant wielding a 12-foot sword -- or four good sword strokes from his equal, or nine spear thrusts from spear-carriers (who have a 1-in-20 chance of even hitting him). If we then make him twice as hard to hit, he's just as powerful as before, without all the hand-waving of hits that aren't hits, non-injuries that need healing, etc.
That's hardly the "wait for the crit" scenario painted as the only alternative to high-hp heroes. The brave Fighter hopes to slay the Fire Giant unscathed, but if he takes a hit, it really hurts. (Sounds right.) If he pairs off against his equal, he expects to take three or four good sword strokes before it's over, and he'll be sorely wounded -- but those blows won't all land in the first or second round. And he's still able to take an ungodly amount of punishment from the spear-carriers -- expecting 180 of their attacks before nine of them land and actually bring him down.
Or we could give everyone one Hit Point (or a single d4 Hit Die) and just ramp up their AC. That seems to be the Straw Man everyone's knocking down.