Less RNG = Boring and linear. How will this style keep me from falling asleep after a few goes? Seems less challenging.
Don't got me wrong, RNG is a pain, but at the same time it keeps you on your toes and forces you to be more proactive. Personally i don't want to manage a resource, I've had plenty of that with mana management with Arcane and there are many more classes with this style.
Also we would suck in AoE. I want fire to be an on demand style. Maybe this heat idea could be a CD of some sort. Bring back CD management.