I've waited for this feature for a long time but it still doesn't happen. So here it goes:
As a Photoshop user I often want to update a layer style that is being used on multiple layers. Meaning I change in one place, and all layers using that style will get updated.
As of now, you're limited to workarounds that are either complex or not applicable to the specific use case.
Suggested solution: Add a "linked/dynamic/whatever" layer style. If this layer style is changed anywhere, whatever layer that is using it will be updated accordingly. This should go for both normal layer styles and layer style presets.
This would increase productivity a lot when doing complex design and wanting to try out things quickly.