I've seen several questions recently about whether Seed of Corruption (SoC) or Rain of Fire (RoF) is better for a given spec, none of which have been able to find a mathematically supported thread comparing the two.
I'd appreciate feedback on the following argument in the worst case of the Destro lock, that SoC outperforms RoF in dps. So, as of 3.3, SoC should be the AoE of choice for all specs.
For simplicity we will assume hit capped, but it is easy to extend the model.
Also, this analysis assumes seeds explode before the next seed finishes casting, justified either by the damage output or tab seeding.
Let N be number of targets.

crit rate as decimal for RoF

crit rate as decimal for SoC

crit multiplier for RoF

crit multiplier for SoC

damage non crit RoF

damage non crit SoC

haste as a decimal

cast time for tick of RoF in seconds

cast time for SoC in seconds
Recall also RoF ticks every 2 seconds before haste.
For i either r (RoF) or s (SoC), we have
Total Expected AOE_i damage:
which is equal to
Expected AOE DPS_i is
Total Expected AOE damage /
Destruction spec sample values using Chaotic Skyflare Diamond (CSD) Meta:

from Devastation talent

(extra from CSD)

(extra from CSD)
Plugging these values into the previous formula, we obtain:
Total RoF Expected AOE damage = 7634
Total SoC Expected AOE damage = 9680
RoF AOE DPS = 4370 damage/sec
SoC AOE DPS = 5566 damage/sec
So, Seed of Corruption is the clear winner at this gear level even for the worst case of the Destro lock.
It is also fairly clear there would need to be a very sizable decrease in the gap between

and

for RoF to be competitive. According to wowwiki, the spellpower coefficient for SoC is 16.6% while for RoF it is 8.3% per tick. This means even at higher gear levels, SoC will continue to dominate RoF.
Please comment and advise of any needed correction.
Wowwiki SoC Page:
Seed of Corruption - WoWWiki - Your guide to the World of Warcraft
Wowwiki RoF Page:
Rain of Fire - WoWWiki - Your guide to the World of Warcraft