2H is better for leveling for a number of reasons:
- Rally: easily accessible Major Brutality and a burst heal that scales with maximum stamina and weapon damage - since you want the Molten Armaments morph for damage and you will not unlock Vigor until later on.
- Brawler: good AoE ability and a shield that helps reduce damage from mobs
- Reverse Slice: DK has no execute and this helps kill enemies fast.
- Forceful and Follow Up passives dovetail quite nicely with the heavy attack bonus from Molten Armaments and give increased AoE damage
For leveling/grinding I would suggest a cheap set of crafted gear: 5 Hunding's Rage 3 Night Mother's Gaze 3 Agility. Have it crafted at in Training trait at whatever CP you are; if you are already at CP160+ there's little point in grinding but if you insist have it crafted at CP150 to save materials.
I want to reach ~400 cp then i will farm sets etc