I was testing this spec:
https://www.grimtools.com/calc/Q2zmyodN
Trying to build a pierce retal paladin.
turn out, the physical retal in RF cannot be converted to piercing through oathbearer’s 100% armor piercing:
Why oh why Crate.?? 
Hope you consider to change it and make pierce retal build a reality.
We just consolidated Retaliation into a few select damage types…why would we undo that…
Why not? I thought you makes most of the retal to be phys because it can get easily converted to other damage type?
My elemental retal still get converted to pierce from oathbearer’s conversion though.
Armor piercing doesn’t work that way anyways. It only converts phys damage that’s being “channeled” through your weapon. For example, armor piercing won’t make the phys damage on grenado into pierce damage either.
It’s not. Try with annihilation relic with any 100% armor piercing. that phys will all be converted to pierce. In grenado case, all that phys should be converted to pierce if you add some item skill mod that give some WD to grenado.
Anyway, sigh, on to test another concept I have.
And annihilation proc has … WEAPON DAMAGE 
You need at least 1% weapon damage on the skill that you are trying to convert the physical damage to pierce damage via armor piercing. Retaliation damage is classified as flat damage, therefore it can not be converted via armor piercing.
I know that, sigh.
Your statement on retal is misleading though. Flat phys damage attached to a skill that has WD can be converted to pierce. Phys Retal added to attack just cannot be converted to pierce because crate doesnt want that. The same as any RAtA is not scaled to WD and total damage modifier because Crate doesnt want that.
What I said in this thread is, Righteous Fervor, which is a WD skill that has RAtA, cannot convert its phys retal to pierce with armor piercing. Because crate doesnt want that.
I think Crate is still tweaking RtA. If you remember it was pierce, then all physical, then some physical went to elemental.
The WPS RtA spam also needs a look but is probably low on the priority.
Wpn armor piercing is a funny animal, as you only need one weapon to 100% convert everything (except retal?). So idk.
I am just a bit disappointed, because pierce retal Dervish will be really interesting.
On a side note, that phys-pierce retal oathbearer actually has faster dummy killing than non retal oathbearer+SG set. Oathbearer as a gun, although it looks so powerful on paper, actually not really that good in practice.
Oh I already tried that. Thought armor piercing would work so I slapped in derp slicers along with stoneguard on a dervish. Actually made it jn game cause paper stats were good. Then I looked at RF tooltip and it’s all phys. Damn.
Yeah. Sad panda.
I was thinking to make an acid retal Dervish, but the skill distribution will be a big challenge. It will need an enormous amount of +skills.
Devo will also be a challenge, as there are no exclusive acid devo and phys retal devo is on the opposite side of acid.
You can try sacrificing an item slot instead and go for a plaguebearer green or unchained might so you won’t have to pick a flat RR devotion. Rumor is kinda easy to slot into the usual bulwark route.
Plaguebearer ganarvakar bla bla bla? Hmm, seems like stoneguard+misery+unchained might will be better for more+skills. Will go to theorycraft realm after office hours. Lol.
Yeah. Acid has enough retal gear that you can afford going for a non retal weapon
