From MMO-Champion, the latest PTR notes:
# Spiritual Attunement: Removed from trainers. It is now available deep in the Protection tree for 2 ranks at 5/10%.
Good. I'm not convinced by talents specifically required for a role to be viable (imagine if Prot Warriors couldn't regen Rage from damage without a deep Prot talent) but as compromises go this is reasonable. Holy and Ret is out of luck for off-tanking roles ('Dual-specs won't affect how we design classes'? yeah, right) due to a lack of sufficient mana regen in Prot gear.
Thanks to Will in comments.
There is a curious change on the PTR. It seems that Spiritual Attunement no longer exists for a lot of Paladins. Keen to get the run-down on any undocumented changes I logged into the PTR and this is what I discovered.
Paladin #1: Janae
Janae was the first Paladin I copied across, and as you can see she has SA Rank 2 (but not Rank 1) in her Spellbook and regens mana correctly from a heal cast on her.
Paladin #2: Muggins
Muggins was the second Paladin I copied across. She has neither Rank 1 nor Rank 2 in her Spellbook and they aren't trainable. When healed she does not regen any mana (and no, it wasn't a self-heal or overheal). Both these two characters are Jana, copied from Live to the PTR about a week apart, so they both have the same baseline skills learnt.
Finally, I thought to check whether the trainer has the skill available anywhere in the list of skills to train. I created a lvl1 Paladin (Sztest) and ran her over to the Paladin trainer in Stormwind. This is what I saw:
My gut instinct is that Spiritual Attunement is in the process of going the way of the dodo, and the changes to Guarded by the Light are designed to allow Protection to function without the mana regen on heals mechanic. The aim of all this is of course to reduce the mana regen'd by Holy on fights with heavy AoE, but this seem like a very roundabout way of doing it. I'm also not convinced that Protection can sustain a decent threat rotation without the sort of Mana regened from SA, and Ret is certainly gimped by this. Paladin tanking Pre-71 will also become extremely troublesome.
The patch notes, which are due to be updated soon, may shed some light on things. I'll update this post as and when I know more.