Unfortunately, while Disc and Holy share a Tier set this is probably unavoidable. It would be awkward to come up with set bonuses which are roughly equivalent for both Holy and Disc, simply because the spell usage is so different. You'd end up with abominations like the Feral Druid set bonuses; things like "Your Penance spell gains +5% crit and your Circle of Healing spell has it's cooldown reduced by 1 second".

T8 and T9 both have one solid and one meh set bonus for each spec. That's not too bad, and of course Holy has the option of going 2-piece of each.

Had some strange things happening last night in Ulduar25. While in my Holy spec for Ignis, I was doing my usual of using CoH while airborne with the flame jets usually using myself as the target...except I was not receiving any healing from the CoH but others were, in fact it was doing some _very_ low numbers generally. I checked that I was using the latest rank (7) of CoH, even re-dragged it to the toolbar to ensure this was the case. However, this was not consistent, I didn't get a proper chance to test it as we were kinda rolling our way through, but on Freya I spent some time watching what was happening.

Target someone, cast CoH and the target would receive no healing but CoH hit 5 targets (I am glyphed with CoH tho) and there was easily 10+ people in range, I keep the same target, casted nothing else in between and waited for CoH to come off cd, tapped CoH again and it hit 6 targets and healed the target this time. I only tested this twice (which I know is barely a test)...I'm hoping one or two folks were recording their combatlogs so i'll post 'em. This didn't always happen tho - sometimes the targetted person would receive the heal from CoH fine...i'm guesstimating a 50% work / didn't work rate.

I've only noticed this issue from yesterday so wanted to see if anyone else was having similar issues.

Read the tooltip carefully. CoH does not necessarily hit the target you cast on.

T8 2pc is +10% crit to PoH
T9 2pc is +20% healing to PoM

Just wanted to clarify that they're not both PoM.

This doesn't explain why it's only hitting 5 targets when there are a lot more in range (and are not on full HP). I have a feeling that there is an issue with the mechanic for the healing on the target not working correctly, hence the references to the target.

Depending on what mod you're using to show the number of targets to hit, it might be a bug or issue there rather than the actual game mechanics.

Some mods, for instance, show heals on yourself as incoming but not outgoing, which means that you would see [5 hits] on one side and then some incoming healing on the other side. It's not really a bug, it's just the way it's set up to show healing. If there's 10+ people in range all needing healing, there's a reasonable chance that you're one of them. And there's a reasonable chance that if you get hit with the first one, you won't get hit with the second one 6 seconds later, hence the 5 and then 6 targets. That would definitely be my guess as to what was happening.

The only issue with that idea is the fact that the third tier 9 set is ilevel 258, meaning those two pieces would be missing 32 ilevels of stats, which is starting to get substantial (larger than the gap from ilevel 200 10 man Naxx gear to ilevel 226 of t7 hard modes and normal 25 man Ulduar armors). I'd have to see the stat loss involved and the frequency that PoH is being cast in t9 content to make the call as to whether or not that set up is worth it for holy. Once you have access to the ilevel 245 gear midtier, that's still a 19 ilevel difference, which is still more than the 10 man Naxx to 25 man Naxx jump (by six ilevels, but still). Again, we'll have to see the gear before making further judgments, but the pure, brute stat loss is something to keep in mind for those two pieces.

Additionally, with the "hotfix" to rapid burst and hand pulse, making them no longer cause spell pushback, does that possibly open up two points in builds? Or is there another encounter other than Mimiron that makes Healing Focus as required? Auriaya can be irritating with it, but it's mostly in the form of flat counterspelling from the guardian. I haven't done Algalon yet, so that encounter is a mystery to me, at least in terms of whether or not the raid damage causes pushback. I can't think of another encounter offhand that causes spell pushback, unless you're tanking by accident. Freya+3? I cleared it recently in 10 man, and I can't remember if Sunbeams cause pushback, or if it is worth keeping for when the little flower adds beat on you.

Where would you put those two points? I'm just curious because the 20 talent points used to get to the 5th tier already are pretty lame. My first 5, always in Holy Spec. My second 5, always in Spell Warding. My next four are always in inspiration and desperate prayer. That leaves with one point to get to the 4th tier (I put in healing focus since I so rarely renew). 16th and 17th talent points go into holy reach and then I'm left with 3 talent points to get to the 5th tier. So I finish out healing focus (so combining with concentration aura it provides 100% pushback resistance), and then toss 2 points into improved renew.

I really just don't see any better places to move those two points.

Kilborne, I don't know about you but usually when I cast a serendipity hasted PoH, it is followed by a non-hasted one as well, if not a third.

Now for pushback. Concentration aura helps, but does not make the problem go away. With two points into healing focus and concentration aura you will not get pushback at all. And if the course of an instance I get pushed back once and someone dies because of it, I would rather have those points in healing focus rather than renew.

Obviously if you are getting pushback on a regular basis then the talent is worthwhile. I just don't seem to be getting any noticeable pushback on the vast majority of fights. I'm still working on normal Ulduar in both 10 man and 25 man, no hard modes yet. Since several of the pushback mechanics that I am aware of seem to have been nerfed recently, I'm just wondering about the overall value of healing focus.
My guild runs fairly druid and priest heavy, so I rarely ever cast two PoH's in a row, and my personal overall spell usage favors instant cast spells heavily. This would indicate that healing focus would be less useful to me than the average priest. Even so I would be interested in how much pushback I experience over the course of an instance. I think this information is vital in evaluating the value of those points. Even though those initial tiers in holy are somewhat limited choice wise, there are still some decisions to be made, especially for priests who are fond of renew.

"And if the course of an instance I get pushed back once and someone dies because of it, I would rather have those points in healing focus rather than renew."

I absolutely agree (although for me I would steal the additional healing focus point from spell warding), but that is kind of my point. It is hard to compare 5% of a renew or 2% of spell damage reduction against an unknown amount of pushback. Those things would be difficult to compare even knowing the values, but without that knowledge you are back to "I like" or "I prefer". I think that if I was experiencing 1+ second of pushback per minute my likes and preferences would be different then if I am having 1 second of pushback over the course of a raid night. So I’m interested in any way that the amount of pushback can be objectively measured.

One place where I enjoy healing focus is Freya (at least normal for me), when there is all the little adds spawning.
At some point, I've some adds on me.

Thorim is sometimes the same for the little adds in the arena, but there, I use mostly instant casts.

Well you should take the points from divine fury first, then put them into spell warding. Also that is 10-man, where you must not have been running concentration aura. Because 2 points of healing focus, combined with concentration aura (especially improved) should net zero interrupts/pushbacks.