Orb of Storms of Squalls should trigger with a 0.5s cd, not require 0.5s of channeling.

Many/most endgame channeling builds don't channel for 0.5s.

Even ones that are completely on theme for the skill - they just don't channel that long.

Exceptions are CwC builds - sure, they usually channel forever.
But Orb of Storms of Squalls seems like it's meant to be useful for ~lightning dmg channeling builds - storm burst, divine ire etc.

If you're playing those and actually hand-casting them, you are either:
(1) stopping channeling before 0.5s because the enemy is dead
(2) stopping channeling before 0.5s because you need to move to survive

so it's just an incredibly inconsistent supporting damage skill. It really seems like it should just be a cooldown.