The whole point to the CDC even mentioning this I believe was some recent research pointing out how a potential zombie apocalypse makes a great case study for any type of outbreak. Tweak a constraint here or there and you get some very interesting outbreak scenarios to study.
For instance, what if the infection vector changes, such that its airborne and emitted from rotting zombies? How do the infection rates change, how does this impact quarantine procedure, and on and on.
These are the sorts of things that the CDC needs to consider as a matter of course for ANY disease.
As for zombies specifically, I think the more important aspect of the mythos is how it relates to our society and our place within it. You could probably keep every aspect of the lore and simply change the infection criteria and you would suddenly have something very plausible. (microbe in the water? asymptomatic pest carrier? airborne or multiple infection vectors? extended incubation time, these are all minimal mutations to the lore)