PBE Changes to Locket, Athene's, and Redemption - Feedback
For those who haven't seen, reference here for the change list that just hit PBE. Go down to the Item changes on that page. It'll be easiest if I just dive right into looking at a few of the changes, so off we go!
(First, a disclaimer: I mainly play enchanter-style supports (Nami and Janna, a little Sona sometimes, maybe), so the focus of my analysis is largely from that perspective.)

Shield now scales off of your bonus HP. This is a pretty good change. It should, in theory, help to decouple the Locket/Redemption build that has taken over since we got these items (especially since the HP on Redemption was lowered). It should feel optimal to be built on the tankier supports, who are more likely to go Relic Shield line where you get 450-500 bonus HP when you fully upgrade it. Add Knight's Vow and Redemption and you've got a pretty good pool of bonus HP to scale up that shield. And adding a Stoneplate later on would be pretty sick with this.
Point of worry: Cho with a stoneplate. When something has 10k bonus HP late in the game, you're looking at a 2k+ damage shield for the team.

I like the change in theory. In practice, this is incredibly messy. Yes, the mana regen to HP regen conversion needed to go. It was pretty underwhelming overall and rarely felt good to buy (when you could get the same passive off Mikael's, with a much better active). The change to convert mana regen to AP is cool. I'd been wanting a way to sneak a little more AP into support builds, since Athene's was basically non-viable before, and the AP was taken off Banner.
But it's flawed. If you want to make good use of the passive on it, you have to buy mana regen. Where do you get lots of mana regen? All the items that build out of Forbidden Idol. And you can't even use both Athene's and Mikael's, so you're down an option there. So you can go spellthief's line with Athene's for a nice bit of synergy between the two. Censer also makes sense with the passive, and the requirement to be able to heal/shield to make use of Athene's. And as long as you're getting the other %healing/shielding items, you might as well pick up Redemption. But let's pause here and talk about that.

On first looking at the changes, I was excited. Lower HP is okay (Redemption/Locket build made enchanters a bit more durable than they probably should have been). Lower base and per level healing? I'm down with that. Frankly, I feel like the heal is currently a bit much. But then... Redemption heal benefits 3x from %healing/shielding stat.
To me, this takes all the other changes we've talked about, throws them on the floor, and runs over them with the car. Repeatedly. I looked at the numbers on it, and despite the base heal value nerfs, the break-even point with current redemption (and the same %healing/shielding stat) appears to be at 20% healing/shielding stat (which functions as 60% increase for Redemption heal). Windspeakers gives 10%. And Redemption itself gives 10%. So... the heal is effectively not nerfed at all. What's more, if you max out on that stat, and the target takes Runic Armor, the redemption heal can max out over 1000 HP.
The raw efficiency of buying the %healing/shielding stat with Redemption is going to further enforce Redemption/Mikael's/Censer as the best build path for enchanters. Mikael's is almost a must now, since by itself it bumps that redemption heal by 60%. Thus, Athene's can be tossed right back out the window, despite the new passive. Especially since making use of Athene's requires that you have a source of a heal/shield for the other part of the passive... If you have a heal/shield in your kit you're already incentivized to build %healing/shielding stat. And if you build that stat, Redemption becomes a no-brainer. And if you have redemption, Mikael's is 10x better than Athene's... etc.
This one thing on Redemption basically breaks it all. IMO, Redemption should ignore %healing/shielding stat, not benefit triple from it. That lets you choose to build the item because you have some heals/shields already, and you get a neat little extra heal that you can even use if you die. But that's it. You should be buying Redemption because it synergizes with your kit, not because it synergizes with the rest of the items you're going to buy.
That actually gets to what my preference for the support items in general should be. I want to buy items that enhance my champion's kit. That's what makes items fun. The %healing/shielding stat is a cool way to do that. But when you start buying items to augment other items, it feels like your kit is playing second fiddle to items themselves.