Tanking leather would at least be used by two specs: guardians and brewmasters. Spell plate is only used by one: holy paladin. Two specs sharing one set of gear is nothing new - it's actually pretty standard.

Currently the game has these gear categories for non-tier armor pieces:
Caster-DPS cloth (all mages and warlocks, shadow priests)
Healer cloth (holy/discipline priests)
Caster leather (as I understand it, resto and balance druids use mostly the same gear with Spirit translating into Hit for balance)
Physical-DPS leather (feral, all rogues)
Caster mail (same deal for elemental/resto shamans)
Physical-DPS mail
Melee plate (frost/unholy DK, arms/fury warrior, retribution paladin)
Tank plate (protection warrior, protection paladin, blood DK)
Spell plate (holy paladin)

The only category with only one spec wanting it is spell plate.

To be fair, the spec thing was a throw-away comment. I've just disenchanted so much leather in my raids in the last month or so (no rogues or druids) that everytime I see a comment about spell-plate, I think about all of the agility daggers and spell-leather that I see drop.

In any case, the major wild card still to be played in all of this is the "active mitigation" model Blizzard plans on rolling out. Since tanks are supposed to care about threat stats again, it might be that bears will want to stick with DPS gear for that reason. If Savage Defense remains as is, for example, you'll still want crit and hit.

The further difficulty is that there may be a lot of changes that are going to be baked into the specs and not part of the talent trees. I continue to suspect that the tanking classes are going to look fundamentally different from their current iterations.

Allison, I don't see how making ret viable with intellect plate is causing problems. No, I don't mean forcing ret to use it. I just mean make a baseline passive for ret spec that converts intellect into strength. BAM! now int plate is just as viable to ret as str plate. obviously they couldnt stack every slot with it, as there is no int plate with hit/expertise, but all haste/crit/mastery gear would be fair game.

@staffan.johansson - Generally Shadow Priests want what you have called "healer cloth" as well. Although I play a boomkin/resto druid, my main is a shadow priest. Spirit for us is slightly more valuable than hit. At least that's what all the theorycrafters say. So I have a lot of spirit pieces, and only a very few hit pieces. It helps that the ten man raiding group I am part of has a mage and a warlock in it, but no healing priests, so the spirit cloth is mine!

I do pass on spirit rings and necks, unless none of the other healers need them, but that's just me.

I'm still of the opinion that Plate-specific tanking gear should be removed, with tanks looking to "off pieces" (Cloaks, Jewelry, Trinkets) for their tanking stats, sans Agility/Strength.

The current system isn't very fair, considering Healers are not expected to carry two entire sets of gear (Spirit-to-Hit conversion, Spirit becoming progressively less important, Spirit being Reforgeable, Spirit being the only "healer stat").

With Tanks using Leather/Plate DPS gear, their damage would scale better with progressing content, and mechanics like Vengeance might become redundant.

@Allison,

Maybe this is another idea for a one-off wow insider column: how to solve holy paladin gear issue?

On the top of my mind, I have 2 solutions:
1. Make ret benefit from intellect like the other poster points out above
2. Make holy benefit from strength on a 1:1 conversion. The other set of problems (balance for holy's melee damage in pvp) can be solved via spec bonus or spec penalty. If you choose Holy, your melee damage is slashed in half but you get strength -> intellect conversion, and expertise+hit -> spirit conversion.

I'm sure there are other ideas, but I'm aware that they might have their own problems too. If you expound on this in the column, and even if your list of ideas and problems that arise from them isn't complete, I'm sure the commenters can fill out the rest. It would benefit some of us just to see the bigger picture and stop wondering "why isn't Blizzard doing this already"

The griping about spell plate will never end. It's a one spec armor type.
Blizzard won't introduce leather with tanking stats on it this late in the expansion. It'll likely be MoP when that happens, when there are TWO specs that can use it. Two specs. Not one.
Spell plate makes me cry at night.

Actually, if you're going for another article, how about this:
Currently, druids have 4 specs with various abilities that are tied to their specific spec with little overlap. Even when cat/bear share an ability (charge for instance) it's different and faerie fire works different for all three specs. Cataclysm improved the model greatly, but it still seems like a Bear just doesn't have as "much" specifically Bear as say, a prot pal or warrior. I never minded on my feral since I'd switch back and forth between bear/cat and it was quite fun, but since they're sort of hitting the spec hard by splitting them to two different trees, will we see more abilities added to each tree rather than worry about this "master class list of abilities" that has sort of bound us?

To bring it to the Plate discussion, Holy Priests using Strength Plate would be unbalanced because of a list of Base Paladin powers that they use. With Mists, the Base List is becoming smaller and the Spec List is becoming bigger (without trees to map out), so it seems a perfect oppurtunity to redesign the holy paladins offensive set with Strength Plate in mind. They'd still use mana though, so it'd take some programming.

A very simple solution to spell plate that seems perfectly viable with the current route that Blizzard has got rolling on spec. design with MoP is to remove plate specialisation form holy paladins (Plate would be Prot an Ret only talent) forcing them into the same spell mail shamans roll on, I see no problem with the one spec of the paladins tier gear saying mail rather than plate in its description window. After all armour really is not the healer’s stat of choice to begin with.

All the talk about having Holy use Strength plate or Ret use Intellect plate don't work. It is not at all comparable to the Spirit as Hit scenario with Elemental Shaman and Balance Druids, either.

Spirit has long been a stat without a whole lot of purpose outside regen and a brief stint in Wrath where mages and warlocks had buffs like Glyph of Life Tap tied to it. So Spirit as Hit counts the most minor of primary stats as a secondary dps stat that happens to have a hard cap.

What people are proposing for Paladins here involves counting the single most important primary plate dps stat as the single most important caster dps/healer stat or vice versa. There is no point where Strength stops being useful for Ret, or Intellect stops being useful for Holy. The only thing that would possibly keep a Holy Paladin hitting as hard as a Ret Paladin or Ret Paladin healing as effectively as Holy are passives that are tied into the spec.

Druids are getting a bit of this hybridization. According to some blues, Ferals and Guardians will have Agility as Spellpower and Balance and Resto will have Intellect as Attack Power. The major difference here, though, is that what a Druid can do is locked into form. A Resto druid won't be able to melee unless they go into Cat form, which will lock them out of most of their healing spells. A Cat won't be able to heal unless they go into Caster form, which locks them out of their melee abilities. One of the level 90 talents will make them better at being out of form, but only temporarily.

Paladins are not locked into forms. They can do everything in their spellbook from the word go, and they have been enough of a pain in the ass to balance in PvP without having Ret's damage output and Holy's healing output start to converge.

Oh, and as much as people complain about Paladin plate, they are not the only offenders. Agility daggers can be used by more than Rogues, but only Rogues ever use them because Enhancement Shaman want slow weapons and Ferals want Staves and Polearms. Agility throwing weapons and Strength ranged weapons (which, granted, are both going away) are only used by Rogues and Warriors, respectively. And after MoP launches, all ranged weapons will be usable only by Hunters.

@staffan.johansson:

Actually there is a slightly largey set of gearsets out there.

There is spell-mail and spell-plate with and without spirit.

With spirit: the healer specs.
Mail without spirit: elemental shamans.

Plate int gear lacking spirit: I have no idea what spec wants this, but its a very common drop that I see get sharded all the time and end up passing over whenever on my paladin (prot/holy specs).
- For most iLevel ranges, there is a plate set that has spirit, and one that lacks it. I've never played a ret paladin, having leveled as prot in BC, but I can't imagine them wanting it either, unless I'm completely wrong in my understanding of what they do. To me this gear seems to have been made obsolete with the launch of patch 3.0 in 2008... so why its still in game I don't know.

I think the only real solution if they're planning on making "tanking leather" and "dps leather" is to make bears and brewmasters strength based again, and the dps specs (cats and rogues) agility based.

Then they could give bears tanking leather with stats we want like mastery and dodge. We could share trinkets and jewelry with other tanks, instead of having what, five classes who all want agility jewelry? That's pretty terrible.

Plus, how would you distinguish tanking agility leather from dps agility leather? They can't do agility and dodge as agility already gives dodge so we'd double dip. Cats and rogues like mastery too. And bears can't block or parry (but it would be nice if we could!)

Giving strength back to bears is the most sensible solution. Plus then I could tank with maces again! Bears and DKs could share weapons. That'd be cool.

@loop
Actually many of the hybrid heals/caster classes do carry 2 separate sets of gear. My restore/balance has two completely separate sets of gear. The secondary stat priorities can be very different, not to mention Meta gems in helms. Example of resto v. Balance, resto stacks haste to breakpoints then mastery. Balance stacks and prays for never limited amounts of haste. Also many shadow priests and moonkin are swimming in spirit/hit and reforge out of spirit. I want more spirit on my resto druid than the hit cap and holy priests want way more. If you are a raiding hybrid who is expected to swing between heals and dps, you need two sets of gear.

@Metric
In a min/max scenario sure, but my suggestion wouldn't be any different in that regard. If my Blood DK used DPS Plate and Tank off pieces, I would still itemize/reforge/gem in favor of Mastery, and for Unholy I would still itemize/reforge/gem in favor of Strength/Haste.

However, to tank AT ALL requires completely separate gear, at a very base level. Forget nuances that only really exist in max-level end-game content. Healer/Caster DPS specs just don't have this dichotomy. And I'm speaking as someone with a Boomkin/Resto Druid and Holy/Shadow Priest, in addition to a Fury/Prot Warrior and Unholy/Blood DK.

Somebody mentioned getting Retribution Paladins to use spell-plate. Maybe they should be able to choose between two sub-specs where they either use spell plate for large spell damage attached to small melee attacks or small spell augmentations on large melee attacks... Clerics in 4th Edition D&D can choose between "lasers" (melee-to-mid-range spells dealing "radiant" damage) and melee attacks, and the two types of abilities use different core stats so if you try to include things from both sides you'll end up fairly weak. It's a decent model there that the cleric I used to play with seemed to enjoy, so Blizzard could pull some ideas for that if they're considering something similar for Ret.

Anyhow, I think making Unholy DKs int-based would probably be the best fit if they're looking to get more spell-plate wearers. They're probably the most caster-themed plate-wearers outside of the Holy Paladin; the Necromancer-in-plate equivalent to the Holy Paladin's Priest-in-plate. Magically animated pet, death coils, heavy on the disease use, etc.