Is it me, or is DRK really isn't that super great, nor super bad.

[BadRNG]

delirium is nice if you don't have a mnk in the pt. but both syphon strike finisher are just ok. i find myself often not doing them, just getting some mp back and going back into the higher dmg enmity combo. and this devalues the DA effect of power slash, as hate is never an issue this way

I don't think you are accounting for the difference between Syphon and Spinning's potencies, when you do Delirium chain is actually higher potency than Power, if only by 10 . Using it gets you syphon though which means more DA SE, much higher potency than any other chain. So Power's DA effect is still pretty useful.