So I just had a thought. Sure the advent in general don't have many ships that really benefit from increased cooldown rate, but they certainly have a few.
What if guidance were changed to the following:
Guidance: A single target allied ship gains 200/300/400/500% increased ability cooldown rate for 3 seconds.
AM cost: 55/60/65/70
Cooldown: 30 seconds
I know 200-500% sounds like an awful lot, but essentially with a 3 second duration it would come down to 6-15 seconds off each of the target's cooldowns over the next 3 seconds. Regardless having the cooldown rate buff "bursted" in a very short time and applied only to a single key target would increase the usefulness of the ability a lot I think.
This would allow for guidance to essentially allow a targeted ships to have quick bursts of repeated ability use every so often.
Honestly the current model of moderate cooldown reduction doesn't really work because on average most advent ships don't really benefit from it. But frankly the benefit of for example allowing an accompanying radiance to open the fight by casting detonate antimatter on two enemy capitalships rather then one in the first few seconds of combat could be immense(though doing so would require a high rank of guidance).
Other potent combos could include casting guidance on a Halcyon to allow it to cast TK push twice in quick succession(providing an alternative in AA to building 2 Halcyons) or casting guidance on your titan to hasten the next Unity mass or chastc burst.
Well perhaps would be difficult to balance, but would create some very interesting new synergies and would certainly be a way to make a cooldown rate buff useful even for the advent.