Cloak of Flame & Heatproofing Interaction

I was struggling with tankiness on my warrior today. I equipped a Cloak of Flame and noticed a large difference but I was curious if Heatproofing notable near the warrior side of the tree would synergize with the cloak? Since the cloak converts 40+% of physical damage to fire damage and the notable has “25% of armour also applies to Fire Damage taken from Hits” would this mean that 25% of armour would also apply to that 40% converted?

It should, but you lose big chunk of your armor.

To help you with tankiness if you're stacking armor make sure you also pick up the following nodes:

Defend with 150% armor against attacks which are 6m further than you.
Defend with 200% against critical hits.
Defend with 120% armor against projectile attacks.
10% chance to defend with 200% armor.

I'm not sure if they currently exist in the game, but in all likelihood, soon we'll get either enchantments or corrupts that can give us "10% of physical damage taken as lightning/fire/cold/chaos."

The cloak is really good, but with how armor works and how much armor you need to actually be somewhat decent, I wouldn't trade it. It's much better you get huge armor on body armor combined with other useful mods than thorns.