You can make Fire Armor tough without Incarnates (but that will make you even tougher).
My Fire/Axe is sitting at
90% S/L/F
68.76% C
86.74% E/N
54.2% Tox
39.2% Psi
95% Slow Resist
That's before the Reactive Defense Proc kicks in for more Resist, and only with 1 Proc of the ATO +Resist (I have it in Blazing Aura, I believe I've seen it double up, but don't recall it being often).
I rely on that and Healing Flames and now with one of the newest patches, Phoenix Rising (not used that often) and Consume for the +HP it gives. 🙂 No capped HP, but the more HP the better the high resists are.