High Five! I love the "Nerves of Steel" idea.

I can't speak about Steel Cyclone as I can see it being useful if the design fights around it(which shouldn't happen but oh well.)

Mercy Stroke does need a huge damage boost to be useful, but I was thinking 500-600 cause full thrust on dragoons has 300 potency and I want to KNOW I'm getting that heal.

I would say remove Storm'e Eye and replace it with Nerves of Steel, move the slashing debuff to butcher's block, the healing debuff to skull sunder, and increase the healing of Storm's Path to 100-150% of damage done.