So upon reaching lvl 58 and acquiring dreadwyrm trance I see absolutely no use for this skill. Let me explain.
The way I understand it, you have to build III stacks of aethertrail attunement. In order to build these stacks you have to use bane, fester, or energy drain. Well, according to my rotation, these skills are situational and never used abundantly.
Let me explain my rotation: As we all know dungeons have two components, multiple trash mobs and boss's, that's it. Lets take a walk through a typical dungeon and observe a smn in action.
dungeon starts, typical pack of mobs 3+. First I use tri disaster (inflicts bio, bio II, and maisma). Next I use bane to spread that across the pack. Next is shadow flair for aoe. At this point further damage becomes determined by what pet I have out and how the other dps is attacking. Usually I have Garuda during pack mobs so I use arial slash for aoe. I also use maisma II for additional aoe. If dps is good, I use blizzard II for even more aoe. In between all that I will use ruin II and ruin III depending on how mobs are dying. Painflare is even more situational. Depending on how dmg is flowing, I'll throw it in right before aetherflow is about ready to re activate.
During that scenario, Dreadwyrm trance is not an option to be excecuted because as you can see, I only use fester during the encounter. Now, when we get to a typical boss, This rotation doesn't change much, but it does change. I typically use Ifrit and keep him on sic so his dmg is just going off as he feels the need. the only thing I adjust in a boss scenario is starting with tri-disaster, but instead of using bane to spread the dots, I use fester to increase the dmg on single target of those dots. the rest of the rotation is similar.
So in both encounters, I am not spamming bane, fester, and rarely, if ever, use energy drain. I just don't run out of mp, even if I lock down and spam blizzard II, which would be the only ability that would drain mp quickly used in succession.
So tell me, when, and how, do YOU use dreadwyrm trance? If it solely is used later, in conjunction with, deathflare (lvl 60) then I have 2 lvl's to go to use it, but even reading the tool tip, it seems like you would be forced to waste, or prematurely activate aether stacks to use it.
I talked about this with my LS and they said it is a smn godsend. Even what I've read on the forums suggest the same. However, I don't see it this way and I implore you to prove me wrong so I can improve and utilize it accordingly.