I would like to propose these changes to improve Pyro sustained damage and to give more incentive to go 51 deep without effecting our burst damage.

Improve Combust. Increase the chance that Fireball can apply the dot and increase the duration that the dot stays on the target so we have a chance to get to 3 stacks rolling. Extend the dot proc to both Cinder Burst and Fulminate. You already have the code in the game you just need to tweak it a bit. 3 stacks of this dot would be a healthy increase to our sustained damage while not having any drastic effect in PVP. If this is too much for 3 point talent, introduce a Improved Version above it requiring more points spent.

Introduce a new passive earned at 32 like Living Infusion or at 36 like Disciple of Flame in Purifier that provides a buff for each point spent above the level the passive was earned.
Burn Baby Burn provides X% chance for single target pyro spells (Fireball/Cinder Burst/Fulminate) to apply a DoT for Y% of the damage of the spell. X and Y increase for each point spent past the level the passive was earned.

Constructive Feedback is appreciated =)