I personally would not.
However I might consider buying a survival horror FPS made by the team that did Call Of Duty if they took the right approach with it. Of course I think done correctly it would be a new franchise, and shouldn't logically use the CoD name.
See, the relative grit and realism captured in some moments of the first Modern Warfare, like the famous "nuclear death" scene, and the simple fact that they were willing to push the envelope with that "No Russian" mission, means that they might be willing to push the envelope far enough to do a game that takes this kind of scenario fairly seriously, without getting into the sort of cartoonish presentation of a "Left 4 Dead", Campy Nazi alternate history scenarios, or the humor involved in famous political figures of yesteryear making a last stand in the white house.
Over the years a lot of people have talked about what a realistic military response to some sort of Zombie apocolypse might be like, given the horrendous treatment of the subject in most genere fiction, given that they want to deal with small groups of quirky survivors, whose story forms a heavy handed morality play... either that or they make the whole thing so ridiculous and cheezy that it's impossible to take seriously.
If they say decided to push things in the direction of some very "back to the basics" black magic zombies so they could ignore the pseudo-science garbage which causes a lot of the problems in most takes of the genere by trying to insert logic into a scenario that has to defy logic to work, but worked on the idea of the military restoring it's command structure and engaging in a rational response, using all the trappings one would expect like calling in air support, using tanks, and acting as a forward observor for artillery when and where appropriate, they could create a rather interesting spin on the idea, sort of trying to capture a "this is what the military responding would probably actually look like", similar to the way they presented military response in the recent "Battle For Los Angelos" (I think I remember the name correctly) to an alien ground invasion.
While using black magic seems to be counter productive to a realistic scenario, I will say that one problem I've always had with the "Zombie Virus" idea is that if the so called Zombies are actually sick people, I don't see why one would have to aim for weak points like the head, or why they would as durable as the scenario usually requires. After all if they aren't actually dead, but resisting injury due to over-hyped adrenal response and lizard-brain violence, puting a few rounds into the Torso is going to solve the problem. In scenarios like that it's hard to justify why they don't need to breath, or how they are going to keep coming with say their heart or lungs shredded. If your going to ignore issues like that for the sake of the genere, why bother to even say it's a virus, and just go back to the whole "Zombies are an occult phenomena and thus don't have to make sense" logic. At least then it's understandable why you might need a head shot, or to fully dismember the bloody things.
Also magic gets around the problem of having to deal with the issue of a spreading infection. As horrifying as a "hot zone" type scenario was years ago, technology for things like communications and coordinated response have increased dramatically. The odds of an infection spreading from a "Patient Zero" isn't really all that likely. Typically they either have to ignore the whole logic of how the virus spread (oftentimes with the excuse that the survivors don't know) or providing snippets of a scenario that doesn't stand up to a plausible analysis as a lot of detractors of the genere will say.
On the other hand if you say that it's caused by a ritual equivilent to what things like the "Great Ghost Dance" was supposed to do, you can justify the magical nature of the attack combined with people not believing such things were remotely possible, for it cropping up everyone all at once, and not following any kind of logical pattern that could be countered, as well as justifying the very specific kill requirements.
All of this is well outside the basic question of this thread, but the bottom line is that I think a company that has no real problem with showing the mass slaughter of civilians in a fairly realistic fashion, along with slow, painful, nasty death, could probably do the genere justice. They probably wouldb't be squeamish about people being eaten alive in nasty, horror movie detail, and showing all the freaky stuff that is implied in most Zombie movies but never actually shown.
To put things into perspective, the idea of horror is to get a rise out of people. In a horror movie you might have the characters go through an empty maternity/pediatrics ward and find all the kids are missing, and the rooms where they would put the newborns trashed an empty. However just imagine a scene where they actually showed this, with zombies chowing down on six year olds, or walking into a room full of newborn babies and going to town like 300 pound gluttons at an all you can eat buffet. All the reasons why that is wrong, disgusting, and absolutly horrifying is EXACTLY why stuff like that should be in a horror game, especially if your splicing it with an action component where the player is going to be killing zombies. It *IS* possible to freak someone out when the protaganist character/player isn't all that paticularly vulnerable. You see zombies chowing down on babies on a security camera, in all the gruesome detail, it's going to hit home, because no matter how buff the hero is, or even how we're pretty sure the good guys are going to win in the end, that still happened and there was nothing you could do about it... and more importantly your never going to be able to unsee that as a player. Horror by it's nature should push people's buttons, and the teams that do Call Of Duty seem to have that talent as you can tell by the contreversy. It would be nice to see them exploiting that talent in a way that doesn't involve politics. They might be able to push the needed buttons for jaded genere fans, the way EA has failed to do it with series like "Dead Space" (at least so far).
