Going by my testing from 2 days ago, when you recast a corruption, the new damage per tick is determined by the following formula:

( FreshDmg * (FreshTicks - 1) + OldDmg * OldTicks ) / (TotalTicks - 1)

Where Fresh refers to new values with your current procs and Old refers to the values from the corruption that's already ticking. OldTicks is the actual number of ticks contributed via Pandemic, so it's capped at 50% of FreshTicks.

Agony has a similar mechanic, but it somehow interacts weirdly with the stacking component so the actual effect is tiny. Unstable Affliction has no such mechanic, it fully recalculates its damage if you recast it.

Although this is a thread for all warlock specs I feel like destro is not being mentioned or theroycrafted much if at all. That being said I personally have a couple questions about destro this tier.
1. Does the warlock community feel like destro is viable as a pve raiding spec this tier? Is it really so far behind affliction as to be overlooked ?
2. For the people out there who are raiding as Destro what are you using as an opener? For instance are you using dark soul at pull and trying to crit as much as possible while building embers or are people finding it better to save dark soul for chaos bolts to get the increased damage from the increased crit?

Finally has anyone crunched the exact #s regarding gilmore of sacrafice versus haveing a pet and the demon training glyph?

I've been running as Destro and I can say it has not been very impressive. Pretty much need planetary alignment to break 50k consistently and AoE DPS relies completely on starting the fight with embers. I will say that when I switched to grimoire of sacrifice, that I did see a significant increase in my dps (approx 15-20%) over running with the upgraded pets.

I haven't run any number crunching though, but pretty much any site I've seen that deals with this is now showing destro at the bottom of the dps tree even behind demo.

The first darksoul on the pull I find it best to spend it mostly on building embers. By the time you are to subsequent darksouls you can use them to dump CB's. CB is like anything else where you are best off using it when you have certain conditions. IE backdraft at 2x charges or less (if the DPET of incinerate x3 > DPET of CB) but with darksoul and/or trinkets up to get the biggest CB's possible. Mana starvation is quite possible so its always best to use a CB than sit oom. Subjective "feel" and personal performance I see a much better result w' grim of sac than superiority (more than the sims would suggest anyhow).

Overall though, compared to affliction or demo toolkits destro just doesn't offer anything competitive right now. My napkin math of the conflag change in 5.1 doesn't indicate it is going to gain much ground (if conflag grants the same amount of embers as incinerate) so its not anything that is likely to change in 5.1 patch. Also if the grim of sac chaosbolt change (25% of CB's damage is applied as a dot over 3 sec) goes live it will interfere with destro's ability to burst on demand since the dot was "ignite munching" on ptr last I checked.

My guess is yes. Ghostcrawler said that in order to fix (read: Correctly fix) the bug with Metamorphosis/Ranged Melee/Touch of Chaos and their interaction with wands, they would need to create new code to handle it. It would seem that they gave up on that and instead went the route of the band-aid. I'm worried that there will still be an issue with Touch of Chaos.

Why would there be any issue with that? If they have removed our capability to attack with our wands while in Demon Form, there shouldn't be any trouble.

As far as i know, they are removing meta-melee just because it selects automatically selects another target when yours dies, which was breaking crowd control, which led to numerous posts about that particular problem.

So, are we even sure that removing the meta-"melee" ability will fix the wand "bug" as a side effect ? I'm asking because meta-melee and wand-shoot are two different things, and imho i don't know if the problem stems from wand+touch or wand+melee, so i definitly hope the solution they chose will be the "right" one.

Use SimulationCraft.org and sim your own character to find out for sure for you.

Generally, Haste > Mastery > Crit until you get above 10% Haste (unbuffed). Then Haste >= Mastery > Crit.

As far as gems, it really does matter what your gear is. Haste and Mastery jump around a lot in relative value, which is why it's best to sim your own character.

Is that really the case, over the range of actual gear sets people are likely to have right now? In my experience (going from all blues to 482 or so, with several sidegrades along the way), the relative value of the secondary stats - as well as their absolute normalized values - tend to change rather slowly, and over a rather small range; for instance, both haste and mastery have scored between 0.45 and 0.50 for a long time now.

I'm definitely supporting the notion that simming your own character is the best route, but am also curious whether other people do experience the rather large (say, over 0.20 in normalized value) fluctuations over the course of a single raiding tier.

Jumping around a lot was probably the wrong phrase to use. From my experience, Haste and Mastery remain very close in value, sometimes even equal. But Haste is usually ahead of Mastery, especially when you start to near a Haste plateau.

They did not make dots update dynamically with buffs on the player, no. Keep in mind you're sacrificing haunt uptime if you use a shard for the dot renewal, so it's not always worth it, and even when it's worth it it's not going to have a huge effect on your total DPS.