It kind of defeats the whole purpose of a deduction game if it comes down to random chance at the end. Most townies are only able to figure out who's evil (at that, very indirectly), **NOT** who the demon is. It's unbelievably frustrating to successfully narrow down the two evil players, only to guess wrong at the end because there's no way of knowing which one is the demon unless you're lucky enough to get one of the few town roles that tells you, and to confirm them. Not to mention that it's possible for it to change who the demon is. It's also, narratively, a little odd that killing an evil character means you lose. 

Add in the fact that the drunk role means even the 'evil' guesses have a big question mark over them, and that roles are *not* revealed when a character dies, means that you can only reliably solve that a character is innocent or evil, not what their role is. 

The game is only winnable because there are only 3 people left alive at the end. This means that all your deductive work will typically only increase your odds of winning from 1/3 to 1/2. It's less time consuming to literally just skip through the entire game without getting any information whatsoever, and just make a guess until you get lucky.