First of all, thank you for your work on this addon.

ISSUE:
Currently, there appears to be an addon conflict between OmniCC and Weak Auras 2 in which, when the OmniCC addon is loaded, Weak Auras does not receive the Global Cooldown from the game,

EXPLANATION:
I use a Weak Auras Progress Texture to track the GCD in a position close to my character. This progress texture cycles (top to bottom) each time an ability that has a GCD is used and allows me to better time key presses.

*When OmniCC is loaded, Weak Auras fails to process the GCD and this progress texture does not fuction
*When OmniCC is disabled, Weak Auras is able to receive the GCD without issue and the texture functions properly

NOTES:
I tested the Weak Auras GCD Progress Texture using the new in-game feature Interface > Game [TAB] > Action Bars > [x] Show Number for Cooldowns "checked". Since the new in-game feature essentially provides the same function as OmniCC (showing a countdown instead of a radial swipe) for the GCD, and did share the GCD successfully with Weak Auras, it's inferred that once OmniCC is turned on, the GCD is not being passed beyond OmniCC. This assumption is made given the in-game feature that provides the same function as OmniCC does successfully pass it, while OmniCC does not. It's as though the GCD from the game is being held up and stopped at your addon and not being shared with other addons.

OBSERVATIONS:
GCD is not being received by Weak Auras if OmniCC is enabled.
The in-game feature to provide GCD as a number (same function as OmniCC) passes the GCD to WeakAuras successfully.
The in-game feature to provide GCD as Radial Swipe passes the GCD to WeakAuras successfully.

5.4 AND PRIOR VERSIONS
Also, before the WoW 6.02 patch, Omni CC had no conflicts with Weak Auras 2 and allowed the GCD to be passed to Weak Auras when OmniCC was enabled.

Thank you for your time. I would prefer to use your add-on over the in game feature as visually your numbers are larger (i.e. easier to see) and your use of yellow and red colors at various points in the cooldown cycle make OmniCC a better way to discern the progress of GCDs.

OmniCC cannot "block" the global cool-down in any way.