Hello Shadowlora,
Without logs, it is difficult to say precisely what you can improve upon from the standpoint of your rotation. However, based upon your armoury, I suggest that you adjust your gemming, enchanting, and reforging to the following for Demonology :
http://chardev.org/?profile=298304In essence, you want to maintain 1996 or slighty greater haste, and prioritise Mastery after that. Intellect is far and away your most valuable stat, so I changed your gems to net you quite a bit more INT. I strong encourage you to use epic gems where possible. particularly in BiS pieces like your cape, if budget is a concern.
Also, you are currently using a +30 Intellect enchant on your cape. There is a +50 intellect option that would suit you much better.
From what you have shared concerning your rotation, please consider the following
*Your moonwell chalice only applies its benefit to Meta if activated
before the latter.
*It is not necessarly to use a global for CoE if a Balance Druid, Assassination Rogue, or Unholy Death Knight is also attacking your target; either way, you'd want to throw up CoE on the pull and before you Meta
*Immolation Aura takes a snapshot of your spellpower when it is cast and continues to use that value for its duration. If you are not concerned about getting off a second Immo Aura on multiple targets, wait a few seconds to cast the spell until all of your INT and SP procs are active.
*Always be in range for Shadowflame and Immolation Aura. It buffs not only your damage, but your Felhunter's as well. If you cannot be in range, play another spec.
*Doomguard does not interact with Bloodlust at all. Ideally, you will want to cast him at the beginning of the fight in daemon form when your pre-pot, Moonwell Chalice, Volcanic Destruction, and Power Torrent are running. The only haste effects that scale with him are those that change the haste
rating in your character sheet, e.g., the proc off of Insignia of the Corrupted Mind.
*You want to roll a BoD cast in Meta with full buffs active for as much of the fight as possible.
To this end, I'd suggest the following opener, with felguard :
*Pre-potion
*Pre-pull shadow bolt (applies crit debuff)
*BoD (activate MWC on this global)
*Meta+Demon Soul macro
*FG Felstorm
*Immo
*Corr
*Shadowflame
[by now most if not all of your procs should be up]
*Immolation aura
*Soulburn a Felhunter, set it to attack your target
*Recast BoD before it reaches 45 sec on duration and before your procs fall
*Summon doomguard before
any of your procs fall
*HoG (also buffs Immo to full-proc state)
*Standard priority rotation
Incidentally, I have not found Demonology to be useful or optimal on the encounters of this tier - Many feature multiple, long-lived targets, which is an area where Demonology is notably weak compared to the other two specs. I can see it being most useful on Yor'shaj with proper black globule RNG and possibly on Ultraxion, although I have had a better result on that fight with Affliction. Thus yes, I do think it would be worth reforging and regemming for Affliction - and grab some epic gems whilst you are at it !
Best of luck,
Shina