Why would we nerf Redemption/Locket?
I mean, what else is your support going to build?
I mean, what else is your support going to build?

And still
if they aren't nerfed too hard
That isn't bad and is fun to use.
Cause we know no one's building Glory, Banner, Zeke's, Frozen, or ZZ as a support unless it's a very rare occasion, and Crucible is entirely necessity cases only.
Leaves your gold items, vision, and Censer. Tada...
I like building Zz'rot on a support.
It lets me keep a side-lane pushed so my teammates don't have to deal with it (often getting caught out or leaving us 4v5 in the process).
It helps me clear waves and pressure towers too.

Because you can turn literally any champion into a support by building Locket and Redemption. Yes, even Support 
ZZrot can actually be really fun to build. Place it somewhere, get your whole team to wait in the bush that you placed it in, and maul them as they come for it. That sounds like a fun item to me(I build it on Evelynn occasionally just for the surprise attacks).
Fun is subjective and toning down something doesn't mean it will be bad after. Having something be seen as mandatory purely because of it's strength isn't great because it more or less means that support players are pigeonholed into building them or you probably get flamed for it. It probably doesn't matter to most people but I have games were people will attack the support because they did not build locket and redemption. On top of that you have sightstone as well. It's gotta be awful to be a support player but locket and redemption atm are a little ridiculous.
Issue: All the other support items suck, are mandatory, aren't really fun to build and use, or a combination of the three.
When's the last time someone was talking about the riveting experience of using Crucible? They need more and better items while they're in the process of nerfing these items. Maybe scrap some bad items and replace them with new ones.