According to the description this skill does not skill with the magic attribute.
I think it should, or it will get pretty useless in late-game.
Side note: Units that die from burning damage will explode:
This sounds like a unit will explode in case the final damage tick is burning damage.
With this damage over time skill (which ticks quite low) this will happen pretty rarely.
How about: All units that die having the burning debuff will explode? (removing the last hit dependency)