Pyromancer - All the Fire - Build Advice

Started playing recently and pretty much made my build based on previous experience playing Diablo. Only thing I knew I wanted was as much fire damage as I could get, and all the ways I could deploy it.

Ended up with this:

My general strategy is to keep my thermite mines under whatever im concentrating the most firepower into while letting mortar trap hammer away. For active damage I mostly use Blackwater Cocktail and Fire Strike

So far I’ve gotten to Homestead on Elite and im level 83. Ive cleared up to SR 15 on normal without much trouble. Far as I can tell I’m not hurting for damage in most cases, but there are a few standouts. Whenever a boss /hero is mostly unhindered by slows and constantly on my tail with high damage I find myself having to kite more and less time to do any damage. Two specific enemies have given me problems: the first being Acedian Aldric, and the second the boss that can be summoned south of Korvan Sands.

My question is what improvements or changes can I make to my build to be more effective? Are there any points in skills I just plain don’t need?

If you will play only at normal/veteran you can play this version. If you want to play at ultimate… Well… You should try it first and then, maybe, you will find what to change by your own. Most of people here plays ultimate difficulty and for ultimate that’s not a good build

Do you own the expansions? If yes, I can try to give some advise snd show a sketch of good ultimate and endgame build with basic itemization if you want

I do plan on trying Ultimate. And yes I do have the expansions.