
Originally Posted by
StouterTaru
If your Spell Speed is around 900, you won't be waiting on that MP tick, and a thundercloud means your 15 second cycle becomes 18 seconds. At 5 mobs, that's ~780 potency per 3 seconds. Using a thundercloud takes 3 seconds due to server MP tick, for only 710 potency. And that's assuming that the mob is alive for the full 24 seconds.
Flare TC Transpose (swapping TC and Transpose makes the GCD go on for too long in my experience) let's you use TC without any lost AoE time and fit everything inside 15 seconds with 900 SS. The only problem is you can't quarantee it. Clearly we need the ability to store TC procs like Aetherflow and not have them expire until you zone or die.

Originally Posted by
daman4567
If you only consider straight potency. Aoe rotation requires a lot of waiting for mp ticks if you are unlucky, or if you have just enough SS that you cast Fire III within one server tick. Once there gets to be around 8 or more enemies, thunder would definitely not be worth it, but if you find yourself waiting for MP ticks during aoe a lot, the breakpoint is probably a bit higher than 4-5 mobs.
You need exactly zero SS from gear to hit that. However, what you can't have is enough SS to shorten your AoE rotation from 15 to 12 seconds. If at any point after the first Flare you're waiting for ticks, you're doing something wrong or had to dodge. This has been the case since ARR launch. F3 F2 Flare is slightly shorter than the 12 seconds cooldown of Transpose, but is less PPS than the normal rotation. With 900 SS+, a lot of your waiting time is spent after the first tick to cast F3, so you can get the second one and have mana to do anything. I think around 700-750 SS is when you can't just smash your F3 and have to start paying attention.
Let's look at the average potencies per second. Calcs are done for F3 - F2 - F2 - F2 - Flare into looping F3 - F2 - F2 - Flare rotation. Both instant and three second ticks are presented for the first part. Math inside spoilers.
3 mobs: 160,2-189,3 PPS into 170,6 PPS
4 mobs: 204,7-241,9 PPS into 216,5 PPS
5 mobs: 246,8-291,6 PPS into 259,2 PPS
3 mobs: (240 + 540*3 + 1263,6)/16,5 to 19,5 = 160,2-189,3 PPS into (216 + 540*2 + 1263,6)/15 = 170,6 PPS
4 mobs: (240 + 720*3 + 1591,2)/16,5 to 19,5 = 204,7-241,9 PPS into (216 + 720*2 + 1591,2)/15 = 216,5 PPS
5 mobs: (240 + 900*3 + 1872)/16,5 to 19,5 = 246,8-291,6 PPS into (216 + 900*2 + 1872)/15 = 259,2 PPS
Add Thunder into the mix:
3 mobs: 167,5-190,9 PPS into 181,6 PPS or 189,5 PPS (two procs and 21s) or 218 PPS (15s after Flare)
4 mobs: 202,9-231,2 PPS into 219,8 PPS or 222,2 PPS (two procs and 21s) or 263,8 PPS (15s after Flare)
5 mobs: 236,4-269,4 PPS into 255,4 PPS or 252,8 PPS (two procs and 21s) or 306,5 PPS (15s after Flare)
3 mobs: (240 + 540*3 + 1263,6 + 270 + 710)/21,5 to 24,5 = 167,5-190,9 PPS into (216 + 540*2 + 1263,6 + 710)/18 = 181,6 PPS or 189,5 PPS
4 mobs: (240 + 720*3 + 1591,2 + 270 + 710)/21,5 to 24,5 = 202,9-231,2 PPS into (216 + 720*2 + 1591,2 + 710)/18 = 219,8 PPS or 222,2 PPS
5 mobs: (240 + 900*3 + 1872 + 270 + 710)/21,5 to 24,5 = 236,4-269,4 PPS into (216 + 900*2 + 1872 + 710)/18 = 255,4 PPS or 252,8 PPS
After mathing that out, I don't think Sharp Thunder is worth it at even four mobs. Unless you could quarantee a TC after Flare like I mentioned earlier.