Unless I'm completely missing something, whenever I go fire as Torchbearer I find that putting points in Circle of Fire is a waste. It's essentially a DoT that only takes effect in a very small area, and the TB has to actually get next to something and spend casting time just to get the DoT going. Also, this is the second PBAoE spell in the fire TB's reportoir, and since it's much weaker than the other it feels a little redundant.
I'd like to see the radius on this greatly enhanced, have it be cast from a distance, have the damage increased, or some combination of the three. Could even add a mechanic where enemies enter the circle of fire and then catch on fire, causing them to take damage over time even once they leave the circle.
Or, perhaps the skill could be replaced altogether. Could change it into a Fire Wall type skill, cast from a distance. Width, damage, and duration improves with skill levels. Or, maybe replace it with a sort of Flamethrower skill - hold down click to cast it, eats up mana per second while being cast. Distance, damage, mana cost increase with skill levels. Those are just ideas (I'm not saying they're good ones). But honestly, as it is I see the skill as something of a waste. Even if the damage were good, it's still really bland as it stands. That's my opinion, anyway.