So mages and balance druids are there not only because of the damage but also because of the utilities. Marks of wild, intellect, aoe stops, solar beam. They are not super relevant in raid but mandatory in high keys.
Blizzard just fails to see it or maliciously makes that happen.
I’m sure game devs do play the game, but at what level? Heroic and +10s? Sure, it doesn’t really matter all classes are viable.