Maybe kinda late for this suggestion as patch is mostly finalized but wanted to get this out. Lost souls got some nice buffs in the playtest patch with a bunch of flat phys for the Hellhounds. This is great for Chaos hellhound(fiendgaze tome), lightning hellhound(kelpath zoth rings) and even acid hellhound(Yugul rings). However, fire hellhounds get very little from this as the lost souls blocks the one source of pet phys to fire conversion(korvaak’s burning blade). There is some conversion on the Khonsar ring proc but its pretty unreliable. Pyromancer Hellhounds are fun but understandably are a far cry from Conjurors/Cabalists with the massive pet support those classes bring.
My suggestion is to give Fleshwarped Archive some Demolitionist support (50-100% phys damage converted to fire for Flame Touched). This will be a neat buff for Pyromancers without nerfing other Hellhound builds by generic pet conversion.