There is no doubt in my mind that this is the best course. Regardless of the damage loss and mana cost of fireball, pyroblast will give more bang for the buck. However, I want to stop casting both before and after. The reason is that if I accidentally hit pyro during a fight, I don't wanna go into that long caste. So, I use (along with the tooltip)
Then you only cast it when it's instant and it's worth far more damage than your fireball face roll.
I also believe that one should stop casting on combustion. I don't chain them because my living bomb may have expired. I use /stopcasting on combustion as well as pyro but I leave open the possibility that I may need to toss in another living bomb before combustion as I want both up before I hit combustion.
I would add the possibility that I may want to stop casting on an impact proc. I figure I don't use fire blast except to spread my dots so I also use /stopcasting on fire blast. One might have both a key bound to fire blast and a macro that stops casting.
As a caveat, I might add that a hot steak will last through one cast of a fireball. In my opinion, it may also depend on the length of the fight. if I'm running cata heroics with a guildie, I might wanna stop casting. If I'm running DS against a boss, I have time for the fireball, the refresh of living bomb, then the pyroblast. It may come down to whether you are facing a raid boss or a heroic elite.
Edited by Sorciere, 17 July 2012 - 12:21 AM.