I pug LI a few times a week on my tank. I die to the Shaclaw nearly every time, not causing a wipe, I just die when he's almost dead. Almost never wipe, or die, anywhere else in the flashpoint. I've cleared it dozens of times and played every role.
The acid he spits, that does the 5k damage ticks, is completely invisible for me and has been since 1.4.
So saying "If the tank dies here we're ****ed" is, my opinion, pretty wrong. The tank dies in that fight, a lot. The acid does so much damage and is literally invisible for me.
Fair enough, if the group wipes then.. A tank dying in the final seconds is not too uncommon, you're right.. But it really shouldn't happen.. My pretty average geared Vanguard has yet to die on him (rakata/columi), even a fresh 50 Commando healer in levelling greens healed me through it..