Yes, of course the details are different. But I don't feel it's going to be noticeably different in practice. I don't say this from a knee jerk reaction to new ideas or fanbyish defense of sacred cows; I just had a very similar idea some time ago and concluded that it wasn't after all that different in real play.
I admit that it may feel different, since you lose healing surges and wounds at different moments are their names are different, but at the end of each encounter, the results are the same. You have full HPs and a more long term vitality resource has depleted slightly, barring extraordinary circumstances like reaching zero wounds or trivial encounters that deal extremely little damage.
Feel is an important part of the game system. Some people didn't like the 4E rules on diagonal movement. For those people, it felt wrong. But, it was still a rule about diagonal movement, just like the 3E rule. Mechanics that feel properly are important to some players.
The main difference here is that lack of wound points kill, healing surges don't. Players will "feel" a lot more cautious when their PC's wound points are low because the PCs "feel" damaged. It will be VERY different in practice in many cases.
Nobody gives a damn if a PC's healing surges are low. It can go to zero and players might still keep going on to the next encounter (we've done this in our games, especially when something is time critical) because nobody is dead or even necessarily on the verge of dying.
It's a different mechanic and will result in different decision making by the players. It goes beyond just feel, but feel is important. Additionally, the ability to heal wound points will become a factor in the game.
Another thing that will probably change is the concept of Comrade's Succor. In 4E, healing surges feel like the PC is tired, so a lot of players do not mind if their PC gets a little more tired in order for another PC to get a little less tired.
When it's actual damage, though, I suspect that using this type of ritual might be done a lot less frequently.
Wizard PC: "Wait a second, let me get this straight. You want me to take on the Fighter's cracked ribs because he ran out of healing potions? Are you joking?"
Comrade's Succor is a metagaming tool to allow the group to continue on. Change it to wound points and there will be players who balk at it in character because they won't view Wound Points mechanically the same as Healing Surges as you do.
And finally, healing potions themselves work the exact opposite in this model. In 4E, healing potions suck down healing surges. In this model, healing potions give back wound points. The entire healing potion paradigm shifts to a more positive in character one for wound points (i.e. vitality resources increase when healed) compared to the metagaming one of healing surges (i.e. vitality resources decrease when healed).
I just don't see how one can equate the two as being the same when they are so different mechanically and via feel.