I haven't raided progression since Ulduar so I maybe out of the loop.
Do you get more out of your class if you track random buffs and utilize larger spells during that window while you're buffed?
Such as random trinket procs, legendary ring proc, weapon enchant proc.
Example would be... wait for one of those procs before casting healing rain; making the entire 10-30 second duration (depending on talent) benefit from the temporary buff while you cast healing rain?
Or in WoD, if you get a proc after casting a ground AoE spell; does the buff apply?
Another example would be to make a weakaura that alerted you when multiple proc buffs line up to make better use of fire and storm elemental totems?