Anytime i raid with a disc priest i notice my numbers go down with all them shields going about. My guild is different though, usually we run with disc priest, holy pala, resto druid and myself, my cd’s are often called for first. Healing tide is great because it can be cast on the move, so if there’s big raid damage coming and everyone is on the move to stack up then its a good time to use it since we can still move.
Spirit link is a b it different as i see it. There is great times to use it like Kormrok for grasping hands or when we stack up in council for certain abilities but alot of the time the raid is spread out so it is no where near as effective. We just started on Socrethar mythic and theres more usage on that fight though with apocalyptic felburst in there.
Dont feel useless though. We do struggle when disc priest are there but remember we have a lot more going for us than just hps. We have grounding totem (great on Xhul for void surge) windwalk (gorefiend if essences get out) we have ankh so we dont waste a battle res on those progression nights. If the boss dies and your 20k down then its still a kill and you did a good job