Why does Enochian have to be a pain in the neck?

[Bigcat9715]

You can have a badass BLM rotation, then mechanics start to get thrown around, and next thing you know Enochian falls off leaving you stuck with your 2.0 rotation for 30secs. It's really annoying.

Why does Enochian have to be on a timer? Is it to give blizzard 4 a reason to live? Would it be op if Enochian was a toggle instead, but the down side would be that it up's the cost of spells by 10 or 15%.