Would it really be so hard for SE to make the user of the Limit Break invincible during the time it's animation is going off?

DDs wouldn't die if they needed to do a clutch LB to kill somebody (or lots of somebodies, in the game of the caster LB), Tanks wouldn't get dangerously low or die while trying to give the whole group a damage sponge, and healers wouldn't get killed while trying to bring the rest of the party back up... I know there's been more than one time I've needed to use the Rank 3 healer LB to pick everyone up, only to get killed because I got caught in the really long animation time and couldn't escape when I needed to.