Should we be demanding use for Tank LB?

[MahoSenshi]

Yes, Nidhogg EX if >1 people died to bombs/eyes (esp. if one of them is a healer) and you have incoming Akh Morns.

[AsunaStrife]

Yes, Nidhogg EX if >1 people died to bombs/eyes (esp. if one of them is a healer) and you have incoming Akh Morns.

No need for that if all remaining people stack up, have somewhat relevant gear and the healer knows what he's doing, 6 people are fine for the stack... if more died than 2 then it turns into a "if" scenario, yea. But then again, if your team does it properly, it is not needed. There simply are no fights at this point of the content that need a tank LB, ever. Only if your team / raid chooses to do so (which shouldn't be the case).
Back in the past tank LB's were common in some Primals or t13 progress. Nowadays the only real consideration of a tank LB is A8S for the second intermission to cheese it, other than that I don't think you need it anywhere, not even if a healer is dead in just any scenario.