I can vouch for this, at least on 10 man. My guild actually dragged my priest through Naxx for gear because I could survive the dance, unlike our normal healers. Which sucked, because Heigan was one of the bosses who dropped Dying Curse on 25 man, and my lock (much like every other caster) craved that trinket.
Incidentally (and totally unrelated to the OT) Dying Curse/Illustration is still my favorite trinket combo, due to the names of both and lore associated with the second.
Back OT: I'm not sure why listing all these mechanics from normal/heroic bosses is relevant, since LFR removes or dilutes anything that is really deadly. But since I am here, how about Instructor Razuvious? Even if they gave tanks the MC orbs like 10 man, it could potentially be a mess. Likewise with the beams on Netherspite, or the cubes on Magtheridon.