Thunderstorm on jinrokh means you're probably stacking somewhere. Each door of horridon is a good spot for shrooms when you get there, and shrooms act as a short cd lay on hands in the last phase. The tanks are standing in one spot on council most of the fight, so placing shrooms is easy (and also good for sandstorm).
Most fights have some decent use for shrooms now, unlike last tier where it was limited to certain fights. I'll gladly spend 3 gcds where I'm not having to spend mana to get a 600k burst heal off the gcd.