Are all multiple +% damage abilities now additive?

[Magnusharkov]

Hey folks, I don't know if it's common knowledge but quite a lot of our +damage abilities now seem to react additively rather than multiplicatively as is traditional. I thought that just for my own peace of mind I'd like to try and collect all erratic percentage based effects into one thread to see if there. Can anyone confirm whether these numbers are correct? Also do we know of any more abilities that have similar issues. Finally do we know if these have been reported as bugs? I can see how these could be working as intended but in my opinion it makes evaluating talents and glyphs very unintuitive if they stack in this way.

1) Crusader strike base damage of 110%.
Wrath of the lightbringer +100% = 220%
However +30% from crusade is additive and "only" = 253%
Crusade has an actual effect of "only" +15%

2) Templars Verdict, how does this actually work?
235% base weapon damage
+30% from crusade = 305%
+15% from the glyph, is this additive? if so the glyph is "only" +11%

3) Exorcism
Base damage based on AP/SP
+100% from art of war
+20% from blazing light, is this additive and only an effect of +10%?
+20% damage from glyph of exorcism. This appears to be bugged and only ever bases it's damage on the base value of exorcism.

4) Hammer of the Righteous
Base damage based on AP
+30% from crusade
+20% from 2pc T10 (additive, is this fixed?)
+10% from glyph of Hotr (additive, is this fixed?)

[theckhd]

I wouldn't say it's necessarily common knowledge, but those of us who have done testing are aware of it.

[tlitp]

They're finally working as intended, and people now deem them "very unintuitive".

If anything, much of the BC/WotLK mess is gone. Same-class auras are additive, whilst individual aura classes are multiplicative : AW * ArcTac * SavCom * (Crus + WotL + 2t11).

[Magnusharkov]

I'd label them unintuitive as it makes all +%damage abilties/talents/glyphs more complex to evaluate. If I'm looking to gauge the effectiveness of something like http://www.wowhead.com/spell=20238 then I have to know the mathematics behind the theorycrafting to realise that 'oh, due to art of war this talent is only half as effective as I thought, maybe it isn't as important as it looks', I don't think you can expect the majority of WoW players to be happy with this reasoning or to even understand why if you explain it to them.

Also, in your above example it's pretty clear that's one awful set bonus, that's only a 4% damage bonus. Is this intended? Does it make the set bonus broadly of equal power relative to other classes?

edit: btw does anyone know if Inquisition is additive?

[theckhd]

Inquisition should be multiplicative, like Avenging Wrath in tlitp's example. In general, percent-based bonuses to specific spells are additive (Crusade, WotL, 2xT10, 2xT11, etc.). Percent-based bonuses to "all damage" are considered a different type of buff though, and will be multiplicative (hence AW*(Crus+WotL)). Similarly, buffs from other classes will be multiplicative.

What I'm not sure about is whether Inq and AW are additive with each other. In other words, whether it's (Inq+AW)*(Crus+WotL+...) or Inq*AW*(Crus+WotL+...). I would guess it's the latter, but I could make a good argument for either.