Heroism: Urban Myth?

It's pretty common to here people talk about how heroism reduces the global cooldown while no other haste affect does. This is generally regarded as true; you'll see reference to this fact by many top players. (and top shamans)

Consider this post from Zaldinar:

What I then did, was chose a spell that had a cooldown that followed it, Fireblast was a good example, so you could be sure that the cooldown presented was either the GCD or the cooldown of the spell itself. Here are three casts of fireblast and the timestamps that came with them:


2967011.233 - Fireblast started
2967012.378 - Spell success registered
2967012.379 - GetSpellCooldown returns a timestamp of 2967011.235 for start of cooldown, vs our time now of 2967012.379 making a delta of approximately 1.144 seconds, duration of cooldown 1.5 seconds, after success the Fireblast 8 second cooldown begins.

2967153.687 - Fireblast started
2967154.533 - Spell success registered
2967154.534 - GetSpellCooldown returns a timestamp of 2967153.689 for start of cooldown, vs our time now of 2967154.534 making a delta of approximately 0.845 seconds, duration of cooldown is again 1.5 seconds, after success of the Fireblast the 8 second cooldown begins.

2967248.307 - Fireblast started
2967249.248 - Spell success registered
2967249.249 - GetSpellCooldown returns a timestamp of 2967248.309 for start of cooldown, vs our time now of 2967249.249 making a delta of approximately 0.939 seconds, duration of cooldown is again 1.5 seconds, after success of the Fireblast the 8 second cooldown begins.


This establishes the ability to observe exactly how much time is going into the GCD, the 1.5 second cooldown can only be the GCD. When lag forced the success event to be registered more than 1.5 seconds after the cast event, the cooldown registered as having an 8 second duration and starting at approximately the time of spell success.

The question at hand is if Heroism reduces the GCD to account for its 30% spellcasting increase. If it does we should observe the cooldown being a 1.5 * .7 = 1.05 second cooldown. Here comes my PTR Shammy, and some heroism action.

2967773.129 - Fireblast started
2967773.818 - Spell success registered
2967773.819 - GetSpellCooldown returns a timestamp of 296773.131 for start of cooldown, vs our time now of 2967773.819 making a delta of approximately 0.688 seconds, duration of cooldown is 1.5 seconds, after success of the fireblast the normal 8 second cooldown begins.

Three other datapoints of exactly the same results followed (for the cooldown duration that is).

What this means: Heroism does *NOT* reduce the GCD (For the folks that want to argue that it does, wait until the conclusion at the end once I cover haste, because there is something waiting for you there).

I had always believed heroism to not influence the GCD from inspecting fraps footage, but it is pretty deceptive. There are clips where I think it clearly does speed up the rate at which the "sparkle" moves; there are countless threads on this topic but this last series of tests on the most recent PTR seem pretty convincing.

Now onto Fear Ward and Fear DR.