The day after publishing my final installment of the AOE post series, I was informed by a developer that Glyph of Fire Blast is not intended to spread Living Bomb to more than the usual limit of three targets. I have since corrected and updated the posts to reflect this fact.
Mists of Pandaria
Now that we've taken a look at how the rotations for each bomb spell might progress over the course of a minute, and had a look at the way their damage output increases over the course of the timeline, let's compare all four bomb setups side-by-side for each of the three target scenarios.
Important note: The original version of this post included numbers based on the assumption that Glyph of Fire Blast would spread Living Bomb to five targets, ignoring the three-target limit (behavior that was reported by another tester, and either was incorrect or was a bug). I've been informed by a developer that this behavior is not intended; the numbers and commentary below have been edited to reflect this fact.
Finally, we'll take a look at Nether Tempest. Unlike with Frost Bomb and Living Bomb, the rotation when using Nether Tempest changes depending on the number of targets, so we have three separate timelines. Nether Tempest does not perform particularly well with larger numbers of targets; indeed, at ten targets, we start using Blizzard and Flamestrike as the primary spells, with Nether Tempest as filler. The specifics will be discussed before each timeline.
Next (and the last one for the evening), a look at Living Bomb used in conjunction with the Fire Blast glyph. Important note: the original version of this post indicated that Glyph of Fire Blast could spread Living Bomb to five targets, ignoring the three-target limit. I have since been informed by a developer that this is not the case (and if he's reading this, thanks for the information!) In fact, Living Bomb is spread to only three targets.
The rotation and total damage is therefore almost identical to standard Living Bomb; as Living Bomb has only a 1-second GCD, using Fire Blast to spread it only saves a half second over casting it three times manually. The timeline chart looks pretty different, because the ticks and detonations of the three bombs are synchronized, and thus the damage with the glyph will be higher than the damage without at some points on the timeline, and lower at others. The timeline will also look much shorter and simpler; since all five bombs will tick at essentially the same time after spreading, I simply multiplied their tick and explosion damage by three and treated them as single events.
Next we'll take a look at how Living Bomb fares in the same situations. This time around, we'll be using the maximum of three manually-placed Living Bombs. Filler spells are the same as with Frost; Frozen Orb the first time, Blizzard and Flamestrike as best as they fit in between the bomb times.
As you'll see, it's slightly weaker than Frost Bomb at 10 targets or higher, is about equal at 8, and is slightly better at 6. It improves further relative to Frost Bomb with fewer targets.