They wouldn't care about getting their legs blown off or something?
That is mathematically kind of impossible with normal weapons and a first critical, and not very likey on 2nd. I have only had 1 person in 2 years get more than 2 criticals.. and yes, they were a little nervous on that 3rd one, but nothing horrible happened. Besides, it is star wars... they are supposed to do crazy things and get away with it.
If you want a grittier feeling (which I have thought of using in more realistic settings) start with a +30 or +50 (!!!). People will get messed up quick!
The guy in the game I play in got his legs blown off on a first crit.
Remember, you don't need Vicious to boost that roll: getting a second triumph, or some excess advantage, or possessing some talents can do the job. Sure, it's not likely to lose a limb on a first crit, but it's certainly not impossible. I think that's kind of as it should be: you really want to be careful in this system, both of how much you're getting hit, and who you're getting hit by. You don't want to get cocky and ignore even kind of piddly threats, like a group of minions, because there can be some dire consequences for anyone.
I'm not totally thrilled with some of the balance in the system--for example, if you're playing a character who doesn't focus on Brawn, and isn't wearing one of the heavier armor types, you're very likely to get dropped in one or two shots. And it looks like that holds true even if you stack up Defense ratings, because Setback dice just don't counter Ability or Proficiency dice very well.
I have this feeling of dread that somewhere down the line, my Jedi will be fairly well developed, with Defense 3, and Sense Control Upgrades enough to upgrade the difficulty to hit me by 2 twice per round, and have the Blaster Bolt Deflection talent (Ways of the Force), and will still get shot, once, an drop, because I'll only have somewhere around 10-12 wounds (depending on how far along I am in XP), and 2-4 soak, and there are a lot of weapons and character types that can 1-shot a character like that if the land their attack.