But besides generic bandits and guards and stuff, the NPCs are not random in ES games. Perhaps they'd have some premade NPCs to bring in wherever they're needed, but I think when they run out, the shops would probably just close down. They wouldn't have randomly generated NPCs.
We really don't know that as of yet. Perhaps they could have randomly generated NPCs for the shop which basically act as my description above. Something tells me the only reason why this feature is implemented is because the kids on the console complained too much about their favorite shop not being around because the shopkeeper just so happened to be involved in an "accident" that ended their life, and the players didn't have any saves to fall back on besides their autosave.
In reality, I actually like the old system better. There's one shopkeeper. If he dies, too bad. No one is going to be able to replace him, because no one knows as much concerning his wares as he does. Either reload a save, or continue playing knowing that the shop in question is no longer up and running.