The problem with "Instant OFF GCD" abilities makes combat feel less rewarding.

[complexxL9]

The way I see things is as follows (correct me I am wrong):

GCD:
Trigger Action -> Action Performs -> Global Cool down -> Trigger Next Action -> Action Performs -> Global Cool down

Off GCD:
Trigger Action -> Action Performs -> Trigger Next Action -> Action Performs

And with off GCD, you can alternate, without waiting in certain circumstances. like

GCD Action -> Perform -> Off-GCD Action -> Perform -> GCD Action

Off GCD:
Trigger Action -> Action Performs ->0.5-1sec animation cooldown-> Trigger Next Action -> Action Performs->

And with off GCD, you can alternate, without waiting in certain circumstances. like

GCD Action -> Perform -> 0.5-1sec animation cooldown-> Off-GCD Action -> Perform ->0.5-1sec animation cooldown-> GCD Action

here you go.