The way our table handles it is that at the death of a character you can flip a destiny point for them to miraculously survive somehow but be out of the session (Like Darth Maul getting sliced in half and falling into a pit, but surviving to show up again in Rebels). Players can do this, and the DM can also do this. That means you can kill Darth Vader, but the DM just flips a dark side point so that he survives somehow and will be back.
It gives DMs the option to save characters that still have a part in the story to play or are canonical, and also gives players some extra security against cheesy ubercrits.
That feels like a total cop-out. Bringing back Maul was like big flashing red letters on the screen: 'WE'VE COMPLETELY RUN OUT OF NEW IDEAS!!'
Players don't like being rescued by deus ex machine, and they really hate the same happening to their enemies.
If there's no way to change an outcome, there's no stake, and you may as well just watch a movie than play a game.
In all honesty, if players aren't affecting the story, you'd be better off not including canon characters in the first place. FFG have been notably reluctant to do so in comparison to previous SW RPGs.
There is nothing deus ex machina about letting characters survive by the will of the force if it makes a better story in the end. The crit table isn't a better storyteller than the GM, and I play for a good narrative, not rigid adherence to mechanics. The mechanics in the game can very easily produce meaningless deaths for both villains and heroes, and to me that's not an improvement over having them go out in ways that people actually appreciate. In fact if you go strictly by the rules of this game all the hand slicing that happens in Star Wars is nothing but random chance, and every single time it occurs they could have just as well rolled a different crit. Wouldn't have really been a good scene in Empire Strikes Back if Luke had been hit with "Temporarily Lame" before he jumped off the gas mining rig, and went splat at the bottom because overly convenient chutes are a deus ex machina.
I think there is a healthy balance between letting people interact with canonical characters and letting people rewrite the whole story. By simply invoking this one little "he's only mostly dead" clause you can have people blow up Darth Vader and get their win without having the whole timeline unravel. That doesn't detract from the value and originality of the stories your party experienced, it just means that the stories that the movie characters experienced also still happened.
Edited by Aetrion