It effects our dps, but not by a lot. Thats really the only answer people can give you because its use depends on your playstyle as well. If you are doing what im considering doing, and dropping MD, then its a little more important, because you do more combo builders in any given time period.
If my math is right, going from 1 to 3 points in combo training effectivly means that you will find yourself doing, on average, one less DA every 3rd non-combo mastery finisher.
The math i used was
1 to 3 points results in a 9.5% increase in combo point per builder (105% to 115%)
Assuming you use DS once every other build cycle
You end up with 7 chances to proc this 9.5% increase every 2 non combo mastery finisher build cycles. (since if it procs on the last point you need the point it gives is wasted)
This results in 0.66 extra combo points per 10 points you generate
Or 1 extra combo point per 15 points you generate.
So every 7 and a half 'hard(non combo mastery) finishers' you do, you will, on average, get a free finisher.
Thats a 13.4% increase in 'hard finisher damage over time'.
We have to account for the loss of a DA however, because after all that time you save getting to a finisher faster still means less damage from DA. DA is around 40% of a DBs damage. This means that in the end we are only gaining around 8% extra 'hard finisher' damage. I can not be bothered to try and figure out what the extra combo point does, it does something, so lets just call this a 10% increase.
So how much of your overall damage comes from non combo mastery finishers?
Well, that depends, again on if you use MD or not.
Ignoring MD, which is favorable for combo training (whatever the results are, if you use MD they will be even less significant).
In a 10 point two hard finisher build cycle you use 9 builders, ignoring combo training for the moment.
This results in 25*8 + 17 prcent damage, which is 217, adding deadly blows on to this brings us up to 337, so your combo builders result in about twice the damage you get from hard finishers.
9% of the time you get a free 60% damage from a deadly blow combo mastery, since this triggers off builders and finishers, we can say that in the 9 builders and 2 hard finishers you do, that is 11 skills, you will proc combo mastery about once on average.
So this means that 397 damage occures over 12 'skill moves' every time you manually build 10 combo points.
But there is also auto attacks and poisoning weapon to consider. As a rogue you can think of auto attack as doing 10% damage roughly 8 times every 10 skills. In our above example we will go ahead and say over a 12 'skill move' period, it adds another 90%
Poisoning weapn tics once every 2 seconds for 10 to 15, depending on whether you maxed it or nto. we will average it at 12.5% for for this calculation. For our 12 skill move period, lets allow for latency losing us a little bit of time, and say that it adds another 85%
So now, over this 12 'skill use' period we have
217% from builders
120% from hard finishers
60% from free finishers
90% from auto attack
85% from poisoning weapon.
This totals 572%
Now, we have determined earlier than two more into combo training increases your hard finisher damage output by 10%
This means that 120% from hard finishers will theoretically increase to 132%, an extra 12%.
going from 572 to 584 is an increase of 2.2% damage
So there you go. Going from 1 to 3 in combo training increaes your overall damage output by 2.2%
To put this in perspective, ignoring dual stab entierly seems to only lose you around 3-4% overall damage output in my testing. So not raising combo training is somewhere between 50 and 100% as 'bad' for you as taking dual stab off your hotbar and never using it. Do you feel like doing that is bad?
This post is full of assumptions, generalizations, and should not be considered anything more than a very rough estimate. I also just did this as i went, my math could be totaly wrong. I don't think it is, but i take combo training anyway since i have the free points and i like how it gets streaky sometimes with combo mastery and makes me really flashy with all those deadly blows. This is how you figure it out though! If you want to be sure do as i have done and check your math. There are plenty of people who leave it at 1 and do just fine.
EDIT: I just thought of a very easy way to test this. Ill simply fight practice dummys and make sure i always ignore combo training procs, always use 5 DA or 3 DA and one DS before a hard combo. Ill go do that now.
Alright. After attacking raid dummys for a half an hour. 15 minutes ignoring combo training procs, and 15 minutes doing it normally. I actually did slightly less damage doing it normally! While im sure this is due to the streaky nature of rogue (there is no way that it actually does more damage), i think its safe to say over 15 minutes, the fact that i actually did LESS making use of combo training procs, shows that its overall insignificant.
Edited by Elysion, 10 June 2013 - 05:01 AM.