What has been your experience with random villager roles in Werewolf?
I've found that if you introduce too much chaos it becomes way, way more difficult for the villagers to figure out what's going on. Even if they were picking 3 roles from among 4 you've added enough chaos that you'll likely need at least one more villager (depending on the roles).

I've played it that way a few times and it's been kind of fun, but it throws deduction and intuition out the window, leaving it pretty much entirely a game of chance. Which, of course, the villagers almost always lose since only the wolves have any real idea of what's going on.