I would more see classes like, cosmetic only. You start out in different outfits depending on the proffesion you choose when you create your character. And the proffessions should be what you were before the zombie outbreak. Like if you were a family man, you start out with casual clothes. If you choose to start as a fireman you will look in a certain way. Just a few examples. I duno. But I vote for no classes which will change gameplay mechanics.