A short version for anyone still reading is that if you like to pull lots of things while solo dots are better. If you are trying to pull 3/time then go for the aoe burst.
If you are fighting a target that takes a while to kill (say an event boss or even a thick lvl 70 boss) dots have time to work and can do more damage.
If that's true and you can use priest/bc without fire active then you might want to report it. There were a number of people taking advantage of the fact that until about 2 months ago you could stack 94% extra fire damage from dots without having fire active. As far as I know any gear that was built like that received the legacy tag.
The mod was changed and specifically says now: while fire magic is active.
I wouldn't call it an exploit per say but more of clever use of game mechanics (that was clearly not intended).
I just looked at some BC gear in my bank and you might want to make a ! about the damage calculation. The extra fire burn from BC mods (not inherently part of the ability) is most definitely getting modified.
You can also use root or mez.