It's Sad but Tank Sona is Actually Superior to AP Sona...
At least in terms of supporting. Sure, AP Sona gets more heals and damage per cast of her abilities, but Tank Sona gets a LOT more use of her base heal and base Q, plus enemy players see Sona and think she's squishy and then dive ontop of her. Even if the burst would be enough to kill you, you'll usually have Flash because as a tank this barely ever happens (and you have Summoner CDR).
Here's the build I played last game: Talisman, Ruby Sightstone, Boots of Mobility + Captain's, Dead Man's Plate, Rylai's Crystal Scepter, and was going to build Warmog's last but they surrendered. Banshee Veil would have been fine too if they had AP.
Did I run oom without Athene's? Absolutely. Did it matter? Not at all! Because I was able to consistently stick around the edge of the battle and press Heal whenever it was up (good thing we have a Chalice passive in the support tree now) and usually get a second Talisman off before a fight was fully over (chases and catching out leads to 30 second fights).
...Not sure how to share specific games but here: http://na.op.gg/summoner/userName=neoseraphi
Went 4/0/20, the dream.