Amperage does come into play because it determines wire temperature which has a considerable effect on the vapor. Taking it to the extreme either way will result in an unsatisfying vape. If you take two wires at the same temperature and different in gauge the vapor will be similar in heat, but greater in volume for the heavier wire.
Amperage determines wire temperature since it's a function of the current flow over the cross sectional area provided there's no difference in the material. So, if you have a narrow wire with less amperage you can get the same temperature as a heavier wire with a higher amperage. Since the thicker wire has more area, current needs to be higher. The result is similar temperature and higher vapor production. That's why people looking to produce clouds use heavier gauge wire.