Stolen idea for death shroud mechanic

I was thinking one of the ways you could make core necro death shroud not suck would be to take influence from shadow priests in wow, particularly with the surrender to madness trait.The fundamental idea is that you build up a resource bar, toggle into a different form with new attacks, the resource begins to drain over time, you do a lot of damage, you fight to sustain your powered up form for as long as possible, and if you run out of the "life force", you die.

Bit of a stretch to expect to ever see something like that implemented in gw2, it'd be too much of a fundamental rework, but it's a cool idea. Let's be honest, core necro needs an almost complete fundamental overhaul.