Well first, try 7/10. I had to switch to holy during Nathria because I was helping with raid leading during the tier and therefore having to pay attention to way more. That on top of keeping up with ramps was a bit too much and I noticed myself messing up on hungering pulls. Still played Disc through dungeons, and even now I’ll play disc in dungeons when I’m feeling it. I would play disc in raid too, but after transferring I joined a guild with a Disc priest, and there’s no fight in the raid where you’d ever need 2.
That said, you clearly don’t know what you’re talking about when it comes to healing, and you do seem roughly new to it. I’m not going to bring skill into this discussion because it’s not relevant. Yes, Discipline is a valuable spec to take even if it’s doing 20% less healing than other healers (though, it won’t be - it will be doing more HPS than that) because barrier as a CD is way too good to not to have. I might have agreed with you if DK AMZ hadn’t gotten nerfed out of orbit and the Kyrian leggo didn’t position them to do an absolutely massive amount of healing. But just having a CD like barrier on fights like guardians/painsmith is extremely important.
The spec’s not dead. Even though it’s not in the spot I’d ever want it to be. Ideally I’d kill Spirit Shell again, re-buff the spec’s damage to beta levels (because the nerfs only happened after SS introduction) and call it a day. It doesn’t look like Disc’s gonna go in a direction that I want it to, but it’s absolutely not dead lmao.