It's most likely your tanks fault, you should not have threat problems on any fight other than Malygos and possibly Sarth +drakes. About speccing into threat reduction, Imp. Drain Soul is better than other options such as Fel concentration as long as you do not need the hit talents.

Why?

Because you gain nothing from refreshing a DoT early. Curse of Agony for example, has increased damage at the end, but it isn't the only DoT you shouldn't refresh early. Remember that a DoT only ticks once every three seconds, and refreshing early doesn't only waste a potential extra tick, it will actually reduce your DoT uptime. Imagine this model: A DoT has 0.5 seconds left in its duration when you refresh. At the exact moment you refresh, it has already been 2.5 seconds since it has ticked, and won't tick for another 3 seconds, creating 5.5 seconds of downtime on that DoT. An optimal situation of early refreshing would occur if you refreshed the DoT exactly three seconds before it expired, but you are still better off letting the duration expire to gain more filler time.

I have not yet seen a Problem with the current Afflic set up, i'm am however egar to see what happens when 3.1 hits but nothing is ever final until its here, but by making less buttons for us to push to make the rotation more easy with give different classes more ways to complain about a lock being OP, I think what blizzard has done with the afflic lock is not to bad, be a lil more happy with a bit more burst damage to get things started off, but none the less comes to a boss fight and still pushing 5k dps, all that means is that you have grown to you spec and don't have to look all over the screen, i simply watch DoTimer and cast shadow bolt as the fill and casting Huant as soon as its up. I do not agree that the warlock spec needs Simplification. but i suppose that goes along the lines of knowing your class.

Heeno is, correctly, saying that clipping dots will decrease the amount of time you have for casting filler spells, in this case shadow bolt. you are also artificially decreasing the spells DPCT, plus you are wasting mana.

Currently, you want to get as close to clipping a DoT as possible while making absolutely sure you don't clip it. Conversely, if you do clip it, you want to clip it by a lot and not a little. It's discontinuous and rigid. From a purely gameplay, not balance, perspective, affliction would be smoother and more flexible if refreshing UA .001 seconds early was only a .001% DPS loss, the way that refreshing it late is a .00001% DPS loss. More abstractly, the goal of a DoT is simply to protract the damage and have it be pro-rated by duration, but the quantization of it is on the scale of spellcasts, so that the granularity has real and non-trivial impacts on play decisions and that deviate from the intention of pro-rating.

Assuming unlikely proposition that it would be decided the dot refreshes WILL change, and that it would be YOU (and I mean all of you) who will decide how, which option would you prefer:

1) Tick like corr/EA: every time you refresh a dot, its duration is reset, while ticks happen completly unchanged at 3sec intervals, their coeff recalculated with stats taken at the moment refresh landed. CoA is unchanged

2) Tick like corr/EA with a tick queue: same as above, only remaining (old) ticks will tick with old amount, new coeff is recalculated when refresh hits, but it doesn't come to play untill old duration runs out.

Example CoA, no refresh

1 2 3 4 5 6 7 8 9 0 1 2 3 <- tick count
WWWWM MMM S S SS 0 <- actual ticks, every 2 sec

With refresh 7 seconds before CoA ends:

1 2 3 4 5 6 7 8R9 0 1 2 3 4 5 6 7 8 9 0 1
WWWWM MMM S S S S WWWWMMM M 0

W- weak tick M- medium tick S- strong tick 0-CoA has expired already, no tick R- refresh hits

3) tick more often - for example every 1 or 0,5 or 0,25 sec. This will just lessen impact of accidental fractionally early refreshes (such as because of eradication). The problem is with some "on tick effects".

4) refresh slack - if you refresh dot early by a set amount (ie 0,5 sec or even OPed 1 sec) refresh hit will get delayed by server, and hit precisely at 0,00000 mark - this will of course >require< you to refresh dots within that window (as far optimal dpsing goes), mess with dot timers, but completely remove any negative aspect to eradication procc.

5) tick stack - as long as refresh hits between last tick and one before that, ticks will be stacked. That means dot will be refreshed early but at refresh +3 sec (or 2 with CoA) there will be ~2x tick (or 4x if pandemic proccs). ~ of course refers to variance to tick power betwen different casts. This again will force all to refesh within "2/3 sec to end" window, but should help immensely with eradication and cast queueing.

6) yet someting else - do tell

7) I do not want any change at all

I'd go for:
6) duration stack
When a dot gets refreshed, the left over duration is increased by the dot's duration, up to a maximum of 2x the dot period. Ticks continue at the expected time. That way you lose no casting time and no DPS under any circumstance.

I'm not really clear on why everyone thinks refreshing dots early being a dps loss is a problem. Why shouldn't it be a dps loss? Other classes and specs have to be able to prioritise their spells/shots/attacks, so I'm not sure why affliction/warlocks should be any different. Isn't it one of the things that helps differentiate good players from bad?

Perhaps you can elaborate on which classes/specs you are describing here. In my experience with other classes, priorities are governed by waiting for abilities to come off cooldown or for the GCD to complete. In both cases, once a priority is set the given ability can be spammed until it may be activated. Conversely, dots must be timed precisely and, for non-instant-casts, must be timed prior to completion of the prior DoT keeping in mind cast times per ability (which change, of course, with haste procs).

I'm not saying I do not enjoy the challenge of Affliction, something I am new to, but it is vastly different from other classes / specs I have played.

Edit: typo

I'll take option 6 - something entirely new.

Make it so that DoT effects continuously do damage over their duration - every 1/10th of a second 'ticks' or something of that nature. If anyone ever played Guild Wars, and was familiar with necromancer life drains, I'm referring to something similar to that mechanic.

In doing this, they could actually allow your haste rating to reduce the total duration of the DoT spell, so it would do the same amount of damage over a shorter period of time. It would be nice if we actually scaled with all of the caster DPS stats directly, as opposed to only some of our DoT's scaling with crit, only really getting the GCD lowered from haste, etc.

Wishful thinking, but damnit Martin Luther King Jr. had a dream, so I can have one too.