The insanity drain is fine imo. Yes, huge fucking hit in the face early on in the expansion, but as I previously mentioned: Look at what we're gaining down the line. A play style like ours simply can't be strong early on in this expansion. Its exponential increase in output is just too high. Have you watched Viklund's stream recently? He did A MILLION DPS with StM and the Legendary Shoulder. 1 MILLION. Clearly we're capable of actually doing damage when given time to ramp up. What Blizzard needs to improve is the clunkiness of the specc. Because having to refresh DotS is fucking garbage, sorry.
Not saying I disagree with you - Insanity drain should be looked at again. It's just not a "priority" in my eyes. But I might be wrong, who knows!