Imagine for a moment that you have 50 max-level characters in World of Warcraft right now. However, you also need to have 50 alts in World of Warcraft Classic. What are you supposed to do? The answer, obviously, is that you should seek help for the alt addiction you seem to be suffering from. But the other answer is that you should relax because players will be able to have a maximum of 50 WoW Classic characters regardless of how many characters they have in Battle for Azeroth.
Players will be limited to one faction on PvP realms and 10 characters max on a given realm, so you’ll need to be doing a lot of server-hopping to actually reach that character limit. Still, it’s welcome news that the two character limits will be entirely separate and have no linked concerns. Make alts as you wish! You’ll have plenty of space to let them cavort in the Barrens, as was intended.