MMO-Champion, doing their usual sterling work, have datamined the current bonuses for the Tier-10 Relics. They all follow a similar theme: stackable bonuses useful to the spec triggered by a skill in their general rotation. They don't, in the main, represent as much of an upgrade over Tier-9 as T9 did over T8/PvP, but they are still reasonably well budgeted.
Paladin T10 Holy Relic (Holy Shock) - Your Holy Shock spell grants 85 spell power for 15 sec. Stacks up to 3 times.
The T-10 Holy Libram proc is triggered by Holy Shock, rather than Holy Light as in the case of Libram of Veracity (T9). The maximum possible benefit is 255 Spell Power vs Veracity's 234, but it stacks over a period of 10 seconds (minimum) rather than being active after the first Holy Light cast. As usual, pre-buffing before the encounter begins may be a way to overcome this drawback.
Not being a Healer it's tough for me to gauge the value of the Libram, but my gut instinct is that it's not that much of an upgrade and will be fairly low down in the Emblems of Frost spending priority list. In the grand scheme of things 22 Spellpower really isn't all that much and the upgrade of any single set piece to the next Tier of ilvl's should provide a better return.
Paladin T10 Protection Relic (Shield of Righteousness) - Your Shield of Righteousness ability grants 73 dodge rating for 15 sec. Stacks up to 3 times.
Next we come to the Protection Libram. Again, it's a stackable buff, this time providing Dodge Rating in chunks of 75 on strikes from your Shield of Righteousness. It's little better than the Libram of Defiance, the Tier 9 equivalent, but the 20 more dodge rating will be eaten up by diminishing returns in Tier 9/10 gear. The stacking nature of this buff and the fact that it requires a minimum of 12 seconds to stack makes it only slightly better than Defiance and almost certainly not worth investing in until all other tanking upgrades have been purchased.
And your off-spec gear.
And your gems.
And Hierloom items.
Okay, perhaps not Hierlooms, but you get my drift.
Incidentally, check out this thread on Maintankadin to learn more about avoidance diminishing returns.
Paladin T10 Retribution Relic (Crusader Strike) - Your Crusader Strike ability grants 44 Strength for 15 sec. Stacks up to 5 times.
Now, on to the Ret Libram. It is the upgrade for the Libram of Valiance, and at the peak it provides 220 Strength (44*5) vs Valiance's 200. It also has an up-time of 100%, compared with the ~96% of Valiance (due the small chance Valiance has of expiring before the buff is renewed). However, other comparisons aren't necessarily that favourable.
The ramp-up requirement for all the DPS librams have probably been designed to make the Librams less useful in PvP, where an always-up +200 Str could make a heck of a difference. The same was true with Valiance, where it was tied to a Seal less than viable for PvP. It's frustrating, and speaks to bad itemisation for those actual PvP Librams, but there's not much that can be done about it.
Back to PvE and T-10 takes at least 16 seconds to ramp up to its' full potential, rather than the 1-2 secs of Valiance, and 20 seconds is probably a more reasonable estimate. Over a minute of continuous time on-target is needed for T10 to equal Valance's DPS contribution, though admittedly SoV/Cor's own ramp-up will nibble away at that figure. Obviously for full effectiveness you'll also want to cap Expertise and Hit, though you'll probably be doing that anyway.
On the flip side T-10 isn't tied to any one Seal, making it ideal for situations where using SoVeng/Cor would be sub-optimal. Trash packs and encounters with multiple adds are prime opportunities to let loose with this Libram and Seal of Command. Even so, if these sorts of conditions occur a with some frequency the Tier 10 Set 2-item bonus (40% chance of refreshing the cooldown of Divine Storm) would be the first port of call.
So to sum up:
Holy T10 - Small upgrade Protection T10 - Minor Upgrade Retribution T10 - Small to medium upgrade (depending on encounter)
A major part of why these items are lacklustre is the stacking nature of the buff and that they are linked to skills with an effective cooldown. Presupposing a Tier-10 Set purchasing scheme similar to Tier 9's you'll almost certainly want to be buying your Class Set first. But lets not get at all down-hearted, on their own these Librams are great and yet again show just how much of an improvement Tier 9's Relics are.
As with all Patch 3.3 info this is subject to change using the PTR process
*note* Post needs more images