Before I share my opinion here is a couple notes I want to make
1. I have my own Fire/Fire Blaster, who currently has 43 Veteran Levels, so I have many hours devoted to this character.
2. Not sure what your budget is, so when I recommend adding purples, this might be unattainable.
3. Not sure how you like to play characters, as a build only reveals so much
Here are my suggestions
1. You're gonna want more recharge, recharge means your powers come up faster, faster abilities = more damage, and damage is king. (Lots of room to add more)
2. Slotting for Endurance differently, to get more, for less slots. (You wont need consume, also Cauterizing Aura is slotted completely wrong)
3. 6 Slot Blazing Bolt, put the full Blaster's Wrath set in there, you'll see a huge difference in damage. (Also Hot Feet is amazing, So is Burn)
4. If you're trying to get some res/def, there is a better way to do it, though I recommend prioritizing damage.
These are somethings to help min/max a bit better, there are things I do like though.
1. The way Tough is slotted is good, just add the +7.5% Max HP and replace the End/Recharge one
2. 50+5 Hasten
3. Build Up with the Build Up Proc
4. Taking Assault
Just some general tips, up to you to take them into consideration.