GCD timer is to high for melee and ranged physical dps.

[Jamillion]

I can imagine I have 2second gcd under ley lines as a blackmage. But I wouldn't count 2seconds fast if I wasn't a caster.

Level 60 melee classes are constantly using off GCD abilities though, whereas that's not really something you do as often as a caster. The reason Mudra lag was sucha big issue was because it was so hard to not clip your GCD with it. It gets pretty hectic sometimes as a melee, honestly I'd say bards have it the worst because the cast bars from WM don't line up with the GCD so you still have off GCDs to use but you have way less time to use them.