DoT damage = no lifesteal. And without a shield to make you tanky, it’s either lifesteal or health regen with a 2H. Without gear health regen is only provides partly sustain, you can’t just wait there to monster kill themselves because as I mentioned you barely have 100k retaliation damage(And you tried and gear fully retaliation bonused items), they kill you first before they die lol. So you must keep hitting to kill them efficiently but you can’t lifesteal from burn damage either. It might be fun to play in campaign but that’s all. Shieldbreaker is already a ‘‘hard to balance resistances’’ class including with low phys resist. Torch path provides very little of these stats and blast shield+ resilience won’t save you.
You either use the skills to kite or stay there for retaliation/RATA, there is no hybrid of that. Atleast in a serious way. And if you ask me there are much better gear weapond/off-hand or weapon/shield options for kiting as fire caster than Infernal Brimstone. And same for retaliation actually, you can do better fire retaliation build with shield.
So if the weapon atleast provide physical>fire conversion, atleast we can get more damage from RF(this part will do some help for sustain), Meteor, Meteor Shower and Rain of Fire and retaliation part stays as thematic.