In this post I’m going to discuss movement speed bonus in Warlords of Draenor, which ones stack, which don’t and how they interact. Rather than me waffling on I think I’ll just quote the developers from the Patch 6.0 patch notes as they explain it far better than I could.
From the Developers
The logic of how various movement speed bonuses stack (or don’t) has generally been inconsistent and poorly explained. Under the old set-up, each movement speed bonus would become more powerful when combined with another, so we would limit what can stack with what, and prevent certain abilities from being used when another one is already in effect. We decided to change the movement speed system to make it more transparent, with rules about stacking that are easier to understand, and with fewer restrictions.
Previously, multiple movement speed modifiers on you were multiplicative, meaning that if you had two different +25% movement speed bonuses, they resulted in a total movement speed of 56% (1.25*1.25 = 1.56).
Movement speed bonuses have been changed to be additive. The previous example with two different +25% movement speed bonuses would result in a total movement speed of +50%. The logic governing which bonuses stack with others has been simplified as well.
- Movement speed buffs that are temporary or could be applied to other players are considered exclusive, their effects do not stack, and only the highest bonus gets applied (in addition to non-exclusive movement speed buffs).