Overall seems good. Though I have some concerns.
Ember: why immolate is a skill and not a passive? It would have been better to make it passive.
Also currently it has a severe downside. Loosing all of your energy is very high price. Maybe so something like games redline? Up to 100% heat it gives damage resist. When you overheat 100 to 200 gives damage amp instead but no DR at all. If you reach 200 you discharge all your meter as a blast and skill resets to zero? As for the third skill. To add to current functionality when you are overheated it would drain overheat and would do an accelerated effect in addition. Is making enemies vunervunerable to to fire.
For the Vauban. 3 looks freaking dope. Though seems a bit too slow. Probably should be fine only if it has giant AOE.