Ok, I'd like to make a pyro, but different games have different restrictions on what sources are allowed, and most guides don't even bother recognizing blasting as a useful strategy, especially for casters. While this may be true, sometimes I just want to make something burn. The question is, what is the best way to go about it? Warmage? Sorcerer with fire sphere? FS Conjurer or Evoker? Warlock?

Restrictions:
1.Must work on RAW, or RAI must be clearly visible and easily argued.
2.Must kill things with fire. Stuns and such are ok, but the build should not be using Enervation to the point where pulling out a fire spell sounds useless. If another character could reasonably ask "why do you call yourself a pyromancer, when you don't fight with fire?" the build doesn't work.
3.Power level must be in line with at least a tier 3 character. I want to be a useful pyro, not a bic lighter.
4.While cold will be anathema to the build, other energy types are not, as long as I'm always using fire on the enemy(energy substitution and admixture). This means that acid+fire is ok, but acid alone isn't.
5.Must not be setting specific
6.Mentioning dragon mag concepts are fine, but please don't build around them. DMs don't always allow.
7.Must be alignment free. If the only way to play the build is to be the Kobold worshiper of St. Cuthbert's toenail, it isn't going to work.