What can dead Werewolves players be doing?
A simple game variant is that dead people can become ghosts.  This means that they still close their eyes, but do not vote.  During the day, they can still talk and participate in discussions.  Obviously, one's status is NOT revealed when one is killed.  It's up to the moderator to say when the game is over.

This changes the game, since it's not possible to eliminate 'leaders', but it can keep everyone engaged.