I agree with upping the frequency of scripted Tank LB requirements in Raids. I actually thought they were going to do this after they came really close to doing it in WoD, and was disappointed to see in ALEX(N) it wasn't brought it.

Clarifying, not exactly as the OP is suggesting, but certain boss phases are scriped: ifrit ex small nails fill the LB bar, CoD small puffs being killed fills the LB bar. If raid designs provided this sort of scripted (ie free) 3bar LB opportunity that the tank has to LB in order for the raid to survive the boss's next big attack