Good idea to mule splittng steel on Duelist but you should be fine levelling with Ground Slam until Earthshatter

War Bringer is amazing for rage generation to allow the use of Berserk

Defy Pain for armour and max leech (Need Soul of Yugul + Risk Awareness to not die to reflect)
+
Can use 2 reflect reduction implicits on jewels to become immune to reflect

Cry Wolf cluster jewel useful for War Bringer uptime + Perma Onslaught but not mandatory

Can drop Champion of the Cause once you have Enlighten Level 3 and Elreon -mana cost crafts on jewellery

Make sure you have life & mana leech on gear if you're worried about dropping blood rage and/or if you're struggling with mana.

Can swap to Vaal Ground Slam after you have the Rapid Expansion jewel from Act 5 and Vaal Ground Slam (Recommend 38-68+)