There is nothing wrong with a fork. Let's just make sure the exchanges allow the exchange of both. If there are exchanges that intentionally block one over the other, the exchange is not a supporter of free markets.
The only problem is that CURRENTLY, real world merchants like Dish, Expedia, etc will only accept "Bitcoin". They will not bother accepting two coins, so most likely the fork with less mining power will die quickly and there will be miniscule demand for it.
In the future if crypto becomes more mainstream, a fork that leaves two currencies will be more viable.
This might be a good time to look at the alt coins. Are there any alt coins that eventually went offline, or do all alt coins continue to exist, even if they only have two users and near zero value?