I thought the point of season 3 preseason was to encourage supports to start building AP and have their utility scale with it. This is why their damage and ratios were all gutted in favor of this. Now we're seeing items like Redemption (with admittedly pretty cool effects) that we want to build, but we can't if we want our utility to scale. There's also the issue with unique passives - If I want to build a Redemption and an Ardent Censor, I should be able to. If you need to give one a shield boost and one a heal boost do it, but having them unique is severly crippling to support builds, especially since Mikaels and Ardent are already forced to compete for an item slot.
With Aegis getting its MR aura removed and being made more into a tank support item than an enchanter support item, and then Knight's Vow being introduced for tank supports, enchanter/utility/ap supports could really use Redemption to fill a niche that is being left empty by Aegis/Locket previously being a must buy.
I'd like to see some AP added onto Redemption, possibly in exchange for the health it's currently giving, as well as for the heal/shield passive to no longer be unique.
Also, I'm curious what the intended niche night's vow is supposed to be filling.
Edit: Also Meddler confirmed you can buy Ardent/Mikaels/Redemption, and the heals and shields will stack together. You cannot just stack Ardent with another Ardent etc.