What was the point of changing mana in focus?

Why did blizzard change the hunter way of mana? into focus?????
It's gone beyond beating a dead horse. The carcass is just being ravaged at this point.
yea at this point my biggest question is why is it still called arcane shot.
change it's element to something else and have it make slightly more sense.

Heck They could easily give us elemental shots where we basically select what element we want our "arcane" shot to be and call it a day.

but arcane shot sort of implies mana.

incendiary shot implies fire arrows etc

poison shot good name for a nature based shot.

Oil shot for shadow etc.
we need holy arrows that stuns and deals extra holy dmg