To be exact this part "Divine Hymn heals THREE people"
That is an incorrect statement and leads me to believe that this is just a troll post. Divine Hymn heals the 3 lowest persons in a 40 yard radius (standard) and does 12 ticks in total. It will recheck lowest person after each tick. So in best case scenario it will heal 12 low persons (depending on raid health).
Simple fight example: Magmaw 25N i see not 3, not 4, not 5 but 10 people there
If you want more links let me know :P Also with the buff it gives other people their aoe heal gets a nice buff too
ps, Yes Tranquility is still a better raid heal, but their shields suck