While playing Nami I decided the healing/shield one was best for her, but she only has one ability to utilize it, and it's kind of a weak one without AP. I feel she's more about slowing down and catching her enemies.
The same went for Zilean support; I max Q last because I like the utility portion of his kit. This makes the damage-dealing utility ones look weak to me, and he doesn't have any healing/shielding to utilize Windspeaker's Blessing. His ult might technically be a healing effect, but it's such a long cool-down....
I would like to see a second utility support keystone. I would love to see the item CDR from Intelligence brought back, because it helped keeping some vision up, especially in the early game. That alone kind of sounds weak unless it were a very high percentage, so perhaps a movement speed bonus to the allies around you, or perhaps a slow effect reduction to allies like boots of swiftness? Unfortunately I'm aware you're trying to move away from aura effects, so I'll leave all of that up to you.
Thanks for reading!