I have seen various effective builds for low MP, all of them is wrapped around the Grave Injustice - Gruesome Feast - Soul Harvest combo. By boosting your int this way, you can gain significant dps and resistances indirectly, also speeding up the killing and with that promoting the sustain from Grave Injustice.
The builds usually contain Spirit Walk and Horrify with the Stalker rune to pump things up furthermore. The remaining skills are choice of playstyle I guess, for HC Zombie Dogs with Life Link and a Gargantuan really help out.
I did go ahead and check your WD, as a friendly advice I should say that your lifepool seems distressingly low for Hardcore.