And Toebreaker says....
Seriously....? "really really good"
You are telling me a feral kitty with no mastery, a one handed caster mace and off-hand (so almost no weapon damage, please look at the ability tooltips), and half the abilities is "really really good"? Sigh...
As for the examples you gave:
Morchok: Cats/Bears would love to Wrath through Black Bloods. DPS could help heal when it gets rough sub-20%.
The cool-down is too long to have it up for any more than just one of them, and even then it is already tricky for casters to position to do this without killing themselves. It is not a given even for them. And a healer would have no use for weak melee DPS at any point in the fight, it requires constant healing between stomps.
Zon'ozz: An extra healer would be extremely valuable in the black phase. And a Cat being able to switch to Wrath during the black phase would also be super useful, where the adds are all spread out.
Actually DPS during the black phase is just as, if not more important than raw healing, by taking down flails and eyes which are the highest source of raid damage. Having a DPS heal would not be very helpful at all. We already have multiple DPS that can heal with cds, such as DPS with tranq, and they never use it during this fight. Te evidence is already there that this is a no-go.
And again, healers would have no place for weak melee DPS in this fight at any point.
Yor'sahj: The many different phases involved here scream for this great utility. During a black phase, a resto druid could go Cat and deal incredible swipe damage. Or during whatever phase is challenging your healers, any DPS could help heal.
Have you ever healed this fight? There is no room for either. A DPS can not heal strong enough to be worthwhile when a purple glob is up, and would need to be DPSing during any black glob to keep up with adds. They would not have the regen or mana tools to deal with a blue glob either. In reverse, a healer has no place ever going DPS, either they need to be on their strict group assignment during a purple glob, using their mana tools to regen following a blue glob, or straight up healing in a yellow/red. A black would always be in combination with one of the above... and even so, how is this "incredible swipe damage" going to happen with a weapon damage based attack using a one handed (or any) caster weapon setup? Yeh..
Hagara: Wrathspam would be a huge boon to a Cat in Ice phases. And if you're having trouble with damage in lightning phase, a DPS or tank could help stabilize healing.
A big huh when it comes to a cat ever using ranged attacks in this fight?? Really.. huh? Mobility and feral charging to the next target is far better. You want them to plant and cast wraths instead....?
As for healing in lightning phases, for DPS, that might work. But then again I have stated multiple times in this thread that the reverse (DPS healing) has always been much more viable. It's making heals do weak DPS that never really will work.. as you will just remove the healer and replace them with a real DPS if it ever allows for it.
Ultraxion: Most guilds commonly run with a healer that DPSs for the first 2/3 of the fight. They could do that, and have the healer do more damage this way, OR they could go with one less healer and have a DPS or two switch to healing with HotW for the last minute.
It is a DPS race... so having a DPS switch to be a mediocre healer, and steal the valuable buffs, just doesn't make any sense. As for the reverse, it would actually not be plausible for a druid in this case since the red buff was all that really worked for us. But in general you are right that 1 to 2 healers out of 5 in this fight could dps at the start.
Blackhorn: Cats being able to switch to Wrath for range on the drakes would be useful. Or maybe you run with only 1 tank, and have a Cat go Bear with HotW to help tank only occasionally. When there's no healing going on in phase 1, a healer could help DPS.
Honestly you are just searching on this one... really none of that makes sense or fits the fight. Just as a healer, the spike damage is so strong in this fight you are constantly triage healing. Have no clue where you get that there is no healing in P1... And kitties using wrath again is just...lol. Have you ever seen straight boomkin wrath DPS?
Spine: Tons of opportunity for healers to help DPS tendons. Or for a DPS to help tank for periods where the bloods start really stacking up.
I talked about this fight earlier in the thread. As a healer searings are still being sent out and need to be healed, there is only a 10 second portion you could even really use it. The CD doesn't even match in length or repeatability, and you lose your LB maintenance which is our core mana "battery" spell. As a DPS "tanking" ....come on.. have you even seen what it takes to tank bloods on this fight. You really are proposing a moonkin go and tank them? I wont even go into the management of Blood of Netherion on the tanks and the dozen other details...
Madness: Another one where healing requirements ramp up over the fight, and so a healer DPSing in the first half would be very helpful.
And another where mana management is critical. The whole fight is trying to get to the 4th platform with as much mana as possible as a healer. Forcing 3 heals to carry the burden until then, or even two platforms, will have a huge impact there. You will essentially go into the final platform with half the healers having no mana, and to be honest DPS is not the issue in this fight until the healing intensive parts anyways when you lose the aspect buffs..
Even with 6 healers, fully healing and managing mana, it is still a struggle to have mana for the second phase..
I honestly don't really think you have played these specs when raiding... Pretty much any druid I have talked to agrees that this just won't work in PVE except on all all but the most gimmicky "once per tier" fights, and specifically only for DPS healing at times, or a feral tanking. And then there are the finer points for the specs, like resto druids and LB up-time, which is our personal and even the raids mana battery, which does not fit at all with going feral for long periods. I could go on but these are just piling on the already huge heap of badness that is HoTW.
You way over estimate the cross over ability to do these roles. Again, I find it almost humorous that you are telling me a feral kitty with no mastery, a one handed caster mace and off-hand, with half the needed abilities is "really really good"? Or that you think that a pure wrath spam does any significant damage even for a fully decked out boomkin, much less a feral cat during this CD? Really? It will much better than now, which is literally almsot nothing, but is still just pitiful compared to a real DPS. I can't tell if you have a druid or have even played one since you posted on an level 1 alt, but that would lead me to believe that is exactly why you did.
As I have said before, from a restoration druid perspective, if you ever reduce the healing to a point where you could plausibly have one switch constantly, the raid will just bring another DPS instead.
And again, the reverse works much better, so yes, a DPS healing for a portion of the fight has always been much more viable. Which only makes the situation WORSE for a restoration druid. If you make healing so patchy and weak you can have them ever use this watered down and weak DPS, then that same DPS that can heal even better in MoP becomes the perfect replacement for them......