Well, in a sense, we had a zombie in season 1 too, it’s just that Graham was an attractive one, as opposed to your stereotypical zombie. 😉
Cora’s army won’t seem like stereotypical zombies either, I don’t think, (though that shot in the promo where you see one’s hand reach up in the air from the bottom of the screen is an homage to the stereotypical zombie rising from the grave scene). I doubt they’ll be stumbling around, half decayed, mumbling about wanting to eat brains. They’ll just be regular people who are being controlled by the person who has their hearts, which isn’t really different to anything we’ve seen previously, it’s just that this time it’s a large group of people being ordered to kill, as opposed to an individual being ordered to Regina’s bed.