I'm not sure if I'm the only person that does this, but we generally create 3 or so standard Jira Field Configurations shared amongst hundreds of projects.
If a project needs a certain new custom field, we just add it to one of the standards, and limit the context to that one project.
If another project needs it, it's as easy as just flipping the context on the field.
This pattern of usage has made our field configs rather heavy.
With this limit, it seems like we'll need to fracture our field configurations further. I can imagine a future where we have to add a shared field across 10 projects, and have to chase down 10 different field configs to add the field to. Doesn't seem too pleasant from an administration perspective.
At least we aren't forced yet to break away from standard screen scheme configurations.