Personally I would add a skill at pyromancer circle 3 to help massively on flare, just like frost pillar help ice blast on Cryo 3.
I would suggest some kind of low damage but debuffing skill, maybe something that makes enemies more vulnerable to fire, that would also help dps from other pyro skills.
If I were to create an example let’s say: something like Molten ground / Heat wave… A name that inspires AoE.
Skill could be either another DoT of fire debuff, or something more original like a debuff: Enemies affected by the debuff (which is applied on a big terrain [like rain or frost pillar] take more damage from fire skills. Something fixed like 25% extra and more second duration per skill level. Enemies debuffed can be hit by flare.
If it didn’t increase fire damage inside debuff, it could bring beneficial effects to pyro skills, liek increasing duration or hits. For example Fireballs on Molten ground / heat wave, explode 3 times each ,or flame ground and fire pillar having inreased duration, or flare doing more damage on ever consecutive hit. Etc etc etc… Right now pyro is a forgotten class and i think by adding 1 circle 3 skill it would be enough.