Disc can tank a lot, but gosh the play style is a lot different. There is no holy nova, flash heal, prayer of healing, prayer of mending, spirit shell, divine aegis, grace in its original form, rapture in its original form.
Atonement is also fairly different. Now you have to put atonement ON people, by Shadow Mend, Power word: Radiance, PW: Shield, or Plea. Plea is an instant, crappy heal that also adds atonement, but if you Plea a target with atonement, it costs 100% more. Basically you heal entirely with damage and use shields. Shield the tank who gets atonement, get atonement on other members with various ways, then dps until your fingers break.
I’ve been doing dungeons with Ravenshield and it feels weird not actually being a healer, of sorts. I took Schism as a talent just so my finger wouldn’t break using Smite, plus it helps boost the other heals. Holy fire is now basically called Purge the Wicked, but it has a much longer DoT so I have to get use to not applying it as much as Holy fire. It use to be something like Holy Fire, penance, smite smite smite, holy fire, but it ticks for something like 30 seconds instead of 6. It’s hard to get use to. I haven’t played disc since mid-mop though.
You have to talent to even use Penance as a heal, too, and it’s not even ideal. Rapture is now a talent called Shield Discipline and Grace now lets you spam PW: Shield. Oh and PW: shield is on a 6 second cd. No more weakened soul but but only use it 1 every 6 seconds outside of Rapture, which lets you spam it. It’s just odd. It feels like a lot of work because you can’t spam a target to heal up, you have to put atonement on them then spam damage. Nothing to damage? Wellp that sucks.
I think it will be ok, though. Just have to get use to it.