It all depends on the amount of deadliness you want in the campaign.
Wounds/Vitality starts to fail when you look at crits. Even a high level character can be killed by an archer who rolls a 20 and then confirms; 3d8 is likely to kill or severly incapacitate anyone with a Wounds system.
That's the point. You may be a hero, but HEROS die, and not always with glory. At higher levels you shouldn't be hit by the archer in the trees, because you should be aware that that's a good spot for the badguy to sit and snipe on you, so you see it coming. And if you don't, then that shows that perhaps your not able to play a charcter that should be so skilled.
I live by the Wounds/ Vitality system, but what I would say is that it's not for begining gamers, nor those who are absent minded players. You my be a 12 level fighter, bit if you don't wear your armor, or stay behind the wall, you take the chance, just like everyone else, to die. Your Vitality proves how healty, how athletic, how far you can run in a day, or how much energy you have to put into use. But, you are flesh and blood, and just like everyone else, an arrow to the throat can kill you; but not like everyone else, you might have feats that allow you to keep fighting, or skills that allow you to recover and not die, or money which you've smartly used to keep potions or healing items on you to save yourself...there are plenty of reasons why a highlevel player should stay alive, and in my opinion, none of them are based on his unrealistic to take a spear to the head and stay fighting as if nothings happened.
I think what you missing with the crit rule is this: there are no more X, every thing is direct to con, so a sword that does 1D8 damage, does that to con, its not X; so if your con is 15, which is very good, and someone rolls and does 9 (+1 for str) then you're hurt, but your also alive, normal people would be unconcious and about to die in the next round from bleeding.
No one gets it, your ability to survive, to stand, to move after what would've killed a normal person is what makes you heroes and legends.
This system does not work with gamers who want to play Superheros who fall throw buildings and gets hit with missles and shrug it off as if it were nothing.
Wounds/ Vitality is for players who want to play fantasy, but not so that its gets out of hand or boreing to the point that nothing is worth it, you just can run throw or step on or take what ever comes without a thought of it.
Also, you need to look at damage done at the higher levels. It's not unusual around 10th-13th to start breaking 70-100 hit points done in a round by some critters or like-equipped NPCs. If you've dropped hit points without mitigating the damage in some way then around those levels you're going to either go broke getting people Raised, or start working up a new character every session.
