I've noticed, running 4e, that PC hit point totals don't really matter. On a round by round basis, yeah -- if they're bloodied, or if they're low enough that a monster can take them down in one hit, that matters. But just paying attention to their hit point totals doesn't let me know how they're doing, what the pace of the fight is, or how close they are to defeat.
It's a trap I could see myself falling into if I tried to run a 4e game. "What?!? You're out of healing surges? Oh, um, yeah, I guess this is gonna be a short adventure then..." It makes my brain itch to find a way to ditch hit points entirely, and instead give the entire team some form of resilience score based on healing surges and what-not, further melting the individual character into the gestalt of the team.