DRK having a Greased Lightning type mechanic: a refreshable buff with a tight timer, dependent on 1>2>3 combos to sustain. This buff stacks to 3, like GL. Instead of DPS increases though, this buff increases the MP return of Syphon Strike, lowering the returns of Blood Price/Weapon, (or more accurately, the Bloods yield more MP per proc when this buff is absent or at lower stacks).
^I think a system like that would make DRK MP recovery more adaptable, in scenarios where Blood Price's productivity is marginalized there's a ramp up in Syphon Strike productivity (low frequency but high damage), and in scenarios where Syphon Strike is marginalized, Blood Price is providing the maximum of it's potential (AoE, multitarget, high frequency).
Put the blue flames visual on this new buff, switch Salted Earth to a MP consuming spell with potential 100% uptime (hell cost a GCD even, worth it), added HP absorb to Grit'ed Reprisal, and make Reprisal (or some new bada$$ oGCD attack) function like Tornado Kick / Geirskogul, on-demand use that consumes the GL-like stacks.
That's my DRK pie in the sky dream, anyway. Couldn't help but share.