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.
One of the main reasons I wrote up this series of posts was because many people have been assuming that one bomb is always going to be the best option for a given number of targets. But because of the way the different bombs put out damage, this isn't really true. Each bomb puts out its damage in a different pattern, and these patterns can overlap over the course of the timeline. We can see that right away by comparing Living Bomb (both versions) and Frost Bomb in the six-target chart:
As you can see, the three keep weaving around each other, trading places several times due to their different patterns.
- Nether Vortex is very consistent (and at lower target numbers, we would see the other bombs rising above and dipping below Nether Vortex's line at different points in the timeline).
- Living Bomb without the Fire Blast glyph has a fairly gentle waveform; its bomb detonations are staggered, not synchronized, so it rises and falls in waves rather than spikes.
- Frost Bomb, on the other hand, delivers all of its damage simultaneously, resulting in a spike six seconds after every cast. These spikes will increase in size as targets are added.
- Living Bomb with the Fire Blast glyph has synchronized detonations, and spikes twelve seconds after each bomb spread. These spikes will increase in size up to a maximum of three targets (the most bombs that can be applied through spreading), and then will remain consistent in size.
This remains true as we move on to the other scenarios.
As you can see, the two Living Bomb variations and Frost Bomb all scale pretty similarly through these numbers of targets. Frost Bomb increases slightly more than the other two, which scale nearly identically.
You'll notice that Frost Bomb's spikes are larger than before. Additionally, Nether Tempest is falling further behind; it simply doesn't increase as much as targets are added, since each application can affect only two targets. Conversely, however, it will decrease more slowly than others as targets are subtracted, making it a strong option for 2-3 targets.
Moving from six targets to ten, the results at the end of the timeline show the following gains:
- Frost Bomb: 32%
- Living Bomb: 19%
- Spreadable Living Bomb: 18%
- Nether Tempest: 14%
The difference between the two versions of Living Bomb basically comes down to timing; had the timeline ended a few seconds earlier or later, the spreadable version would have ended with better numbers than the standard version.
We can see these trends continue as we move on to our final scenario, ten targets.
Frost Bomb is now starting to open up a lead; large groups are its forté, but as with Nether Tempest, the inverse also applies, and it is weaker than the other options in a cleave situation. With the bulk of Nether Tempest's damage now coming from Flamestrike and Blizzard, it's adopting a curvier timeline, though in this case, it's due to plateaus between Flamestrike cooldowns.
In cleave situations, Frost Bomb is weak, while we can reasonably assume that Nether Tempest is strong, though likely not much stronger than Living Bomb (it does have the advantage of not backloading its damage). In your average AOE situation of around 5-8 targets, Nether Tempest starts to drop behind, while the other three are pretty evenly matched. At large numbers of targets, Frost Bomb pulls ahead.
Nether Tempest does have a couple of unique strengths. First, it only requires one target to be within ten yards of the primary target to deliver its full effect; it can handle adds that are not tightly clustered better than the other two bombs. Second, it scales better with haste than either of the others. While it takes 12.5% haste to get an extra tick out of Living Bomb, that extra tick only represents a 12.5% increase in damage; the detonation damage, half of Living Bomb's total, does not scale with haste. Frost Bomb's DPS does scale with haste, but only by providing more rapid recasts; there is no efficiency gain as there is with the other two. Only Nether Tempest is treated entirely like a true DOT, where 100% of its damage is produced by ticks and additional ticks are added by haste. And given the rapid tick rate, less than 4.5% haste is required to add a tick.
All this means is that, while every Bomb spell has its own strengths and weaknesses, they aren't as simple as counting targets. Target positioning matters, and even more importantly, time to death matters. A matter of a few seconds can make the difference between one bomb or another being the superior choice; you may try to predict the best option based on number of targets and expected kill time, but if one member of your raid fails to start AOE when he should, or she pops a cooldown just before an AOE phase, all your math could go out the window as the kill time shifts to a different point on the timeline, pushing another bomb above your choice.
Now, there are some absolutes. Above four targets, nothing but really spread out target positioning is going to make Nether Tempest the best option, and above ten targets, nothing really touches Frost Bomb. If you're the type of person who swaps talents or glyphs to optimize for every situation, there will be situations where there's a clear best option. But short of that level of min/maxing, it seems like you can count on every bomb providing a reasonable advantage and/or reasonably competitive performance in enough situations that you can make your decision based on playstyle or other preference. Of course, everyone's going to have a different definition of what "reasonable" means in this context, so ultimately, it's up to you how to make the choice; hopefully, this series of posts will be somewhat helpful in making it.