Don’t underestimate the value of +% Physical damage like ulvar mentioned above on gear choices. For example, my build with Ascension up has +2833% Physical damage between gear/passives/cunning bonus whereas yours is +1982.5%. About a 40% total damage increase from yours to mine that helps make up the difference in projectiles.
There is also the massive crit damage bonus that Oathkeeper brings with Divine Mandate.
high crit and +%phys dmg will also help the non converted part go through armor better because crit is checked before armor check
and we could even make some kind of budget version: Shieldbreaker, Level 100 (GD 1.1.9.0) - Grim Dawn Build Calculator (grimtools.com)
(not really sure if there is enough sustain here, as it is only Maul and a bit Adcth from the movement skills and a not so tiny health regen)
tip of scales have some wpn dmg so can steal some life back. There are MI shoulders with vit to phys conversion, but then RIP +3 SJ 
Oh man, lots of great ideas going on here suddenly! Thanks a lot to all of you for reviving this discussion id thought to be dead! Ill have to circle back and reconfigure my Gambit stun jacks build to try this stuff out!
Physical horn of gandarr when?!?!?
As soon as they change Artifact Handling to also affect Horn of Gandarr lol.
Well, it’s not Physical but after the Elemental one, I drew up a GT for this. Truly a build that is reliant on procs.
I think Evil Baka is on a next level of meme’ness
Love it! I really enjoy building around Horn of Gandarr and trying to find the means to get that weapon damage adcth to make the most of it as a dual purpose trash clearing heal skill
Lol yeah, with all that CDR on Horn it looks fun as hell!