The current version of Fay Blessings for healing priest creates toxic gameplay for the healing priest using it and could potentially lead to some balancing problems.
The problem with the covenant is very similar to Blessing of Seasons but I would argue Fay Blessings is a bigger problem that is being under looked.
One of the problems with the ability is the bad game play it creates. This is because the optimal usage case for providing power to an ally for disc priest requires using your major 90 second CD (Rapture) to apply 10 Power Word: Shields to a single target.
I argue this is bad gameplay for these reasons;
- Using Fay Blessings in this manner hinders the disc priest’s own output significantly. While it could be argued this is fine for the support fantasy the covenant is pushing, Power Infusion shares this fantasy as well but it does so in a non-hindering fashion. This is because Power Infusion is off the global cooldown and is not mandatory for the gameplay of Disc Priest. This is not true for Fay Blessings, as Rapture is a core ability for Disc Priest.
- The optimal gameplay of Fay Blessings is terrible to play with. I want to highlight this concern particularly for the high end raiding population would may pick this covenant because it is the most powerful. The gameplay of using 10 Power Word: Shield’s on the same target goes against the gameplay of both disc priest and healers in general. While anecdotal, I have noticed from reading the discourse around this ability, healing priests do not like this gameplay and will be upset if they feel forced into picking this covenant because it is the best one.
- Most importantly, giving 1 player 200% extra resource seems incredibly hard to balance. Rising Mist had to be completely reworked mid-raid because of unintended interactions. Abusing Fay Blessings seems like a gate-way to future balancing problems requiring mid-raid nerfs. The cited example everyone talks about is feeding breath of sindragosa duration. Some testers have been able to effectively double the duration of the normal breath through the use of Fay Blessings abuse.
Everything I have mentioned here can be equally applied to Holy Priest as their best usage of Fay Blessings is to cast 10 Prayer of Healing in a row. This gameplay equally disregards the effectiveness of Prayer of Healing whilst greatly hindering their own output
Ultimately I would suggest a complete rework to the ability. The idea of a support covenant for Priest is a good idea but not executed in this fashion.