Thanks Saedo.

I looked at your parse and log and there are a few things I noticed. I specifically focused on your Festergut kill because that let me see how you did in a nearly optimal tank and spank scenario.

1. You were using Curse of Elements. I'm pretty sure that you were getting the 13% spell damage buff from Creatures so casting CoE was redundant and netted you 0 dps. It's hard to know what raid make-up is like if you just hop in with a raid for a night, but for future reference any time there's a Thunder-Cluck (or boomchicken, lazor-poultry, boomkin druid, etc) or an unholy death knight in raid, you don't need to cast CoE...it'll be a dps loss for you. Whenever you're in a raid with an Unholy DK or a boomchicken (and in DF that's almost always), just cast Curse of Doom instead. Extra 248 dps (or so) if you make the switch.

2. Your immolate uptime was ok...77%. I compared that with Watchesup's Festergut kill this week (he was also playing as destro) and his uptime was about 86.5%. So you've got some room for improvement. Related to this is that it seems as though you're clipping your immolate dot (you're refreshing it--sometimes--before it's done all of its damage. This is why you cast more immolates (than Watches) in a shorter fight and still had a lower uptime. Inspection of your actual log data confirmed this. This is an easy one to fix, just never clip your dots. Even if it means that you don't refresh it the second it runs out. I'm not sure on the exact dps cost of this, but it's not insubstantial. I'd estimate that you were losing in the neighborhood of 200-300 dps from this. (Let's figure low dps loss and call it 225).

3. You'll need to figure out a method of staying on top of your Conflag CD. (I suggest Dotimer, and I'm willing to help you set it up for CDs, Dots, and Auras if you aren't already using it for that.) In your fight you cast Immolate 15 times and Conflagrate only 13 times. To put this in perspective, each time you cast Conflagrate you get on average of 16,133.92 damage (including crits / non crits and the dot conflag leaves at your gear level). During Watchesup's similar fight he cast Immolate 14 times and Conflagrate 21 times. Figuring conservatively, you could probably, with better cooldown management, cast Conflagrate about 19 or so times--and more once you've mastered it. Those extra six conflagrates would net you 96,803.52 more damage (I'm ignoring the negative effect of the 6 extra GCD's for the time being) approximately 445 more dps.

4. I've mentioned your gearing / hit issue previously and it sounds like you're working on that. That will also be a major dps increase.

5. I've never figured out how to determine whether a lock is using a spellstone or a firestone from parses. As Destro (unless things have changed) you should be using your firestone. If you weren't you would also have seen a dps reduction.

I'm running out of time before class. I'll return to this more later.

Edit: I'm back and adding a few extra thoughts.

6. When you're on the move you can also cast Corruption. This shouldn't be a part of your regular rotation, but you might as well be casting something while you're getting into position after you've casted your curse of doom. This can add up to a lot of extra damage on a fight where you might end up having to move around a lot (i.e. Rotface, and really many other). I'd estimate that this might eek out another 150 dps (Watches got around 190 dps from his Corruption in a festergut kill) over the course of a fight--and maybe more on some fights.

7. Chaos Bolt. Technically this is your hardest hitting nuke. In your Festergut kill, you cast it 7 times and it hit for an average of about 13,404 damage. The CD on chaos bolt is 12 seconds. During the fight I analyzed you were active for about 218 seconds. Now, because it's slightly lower on the priority list than Immolate and Conflagrate (because the damage per execute time is lower) you might not be able to cast it RIGHT at CD. However, if you're planning well, I'd say that you SHOULD be able to expect that you can cast it within 3 seconds of your cooldown being up. So, very conservatively I'd say that you should've been able to get off about 218 / 15 = 15 or so Chaos Bolts. That would get you another 8 chaos bolts in a fight of your length, which, for your gear level and spec would net you (approximately) 107,232 more damage. This translates into an approximate dps increase of 492 for the fight.

So, just from those changes, let's see where we stand:

248 + 225 + 445 +150 + 492 + 6690 (your dps from the festergut fight) = 8,250 dps

I'd say that without changing your gear / spec / gems / buffs at all, that's what you should be--ballpark--capable of in a Festergut fight of similar length on a computer with a good frame rate.