@OP, I agree with many of your points (not all) but mostly disagree with the proposed solutions, plus I think there are many other things that might also need attention… Here’s my breakdown:
1.-
I disagree on the Rapture thing, I don’t think there’s a problem with Rapture, but I do agree having it off the GCD would make it feel much better in M+. I specially don’t like the idea of replacing it with Luminous Barrier, I think it’s good that it takes time to spread your Shields.
The one change/improvement to Rapture I think might be worth exploring is making it so instead of giving you a set amount of time it could give you a set number of charges and more time to spend them (say you get 6-8 charges and have up to 40s to use them). This might also open the opportunity for future talents/effect that might suddenly grant you 1 charge or Rapture (re-introducing the concept of getting a strong shield every so often).
2.-
I agree tier 1 talents are a bit imbalanced. Schism is fine imo. I also think TOF is fine it just needs maybe one or two talents that have good synergy to support it (more on that latter).
As for Castigation I do have a pretty cool idea for a change that involves a few more talents too. Basically I would make Castigation cause your sw:pain / POTW spread to a nearby enemy per bolt of penance, then I would replace Shield Discipline for a new version of POTW which no longer has the spreading effect (that was moved to castigation) but returns some mana per tick. (This also covers OP’s point number 3 about Shield Discipline, which I think it’s a boring talent with no real gameplay interactions).
4.-
I agree, Lenience is boring and has very little gameplay interactions. Evangelism is in this row and it’s basically what defines Disc gameplay as a burst AOE healer, I would like a talent that can offer a somewhat different playstile, and I have just the thing for that in mind:
I’d like Disc’s version of Benediction. This involves giving Disc Prayer of Mending which is something I’d like to see as well as a moderate priority / use on the move spell (because I’d also want PoM to go back to instant cast)… The idea is that Benediction causes every jump of PoM to leave an atonement behind (for a reduced duration probably).
This “Benediciton” idea serves two important purposes: 1) Providing an alternative gameplay option for more sustained healing but less burst. 2) Making Disc more approachable for newer players as it requires much less knowledge of the encounter, just use PoM on cooldown. An important note is that Evangelism should remain the go-to option for Mythic Raiding where burst healing is so important (if that’s not the case it means Benediction is OP and needs re-balancing).
5.-
I do somewhat agree about Disc being “punished” by grievous and bursting but I personally don’t think is thaat much worse than for the rest of the healers (as long as everyone brings and uses his own food and/or you bring fish feasts). I’m fine with this specific weakness.
6.-
Somewhat true, I think a lot of it comes down to Disc throughput in 5-mans being quite significantly lower than the other healers. Address that and we are fine on this category (Probably having atonement % transfer being buffed a bit in 5-mans).
Other Concerns I have:
Disc (and Holy too) needs a GCD efficient way to deal AOE damage in M+, it doesn’t need to translate to healing. I would buff Mindbender/Shadowfied to also drop dark puddles on the ground that damage enemies standing on them (that damage does not transfer to atonement healing). This is different from Durids and Pallys using Sunfire/Consecration but achieve the same thing, a GCD efficient way for AOE damage, since it’s a longer cooldown it should be stronger when used.
Spot healing or triage healing is an issue for Disc too, and here’s where I think we should have something big in the final talent row competing with Evangelism and the other talent I proposed (the Benediction-like talent). I don’t have a specific idea but perhaps some form of direct healing help, something aimed to M+ to help with triage healing (this would also very likely interact well with TOF from talent row 1).