In reply to Jesse Petersen.

Jesse,
I agree that ACF or CMB2 can be run successfully without requiring other plugins, and also offer the possibility of building handy data entry elements.

I think they'd allow a plugin like ACF because it offers the non-techie user a very simple interface for creating custom fields. CMB2 does not have any admin interface, although by writing just a small amount of code, one can create very useful interface elements for the user. But a developer is required. I think that's the distinction that they'd draw.

Apart from that, I guess I'll keep my eye on other sources than wordpress.org for plugin frameworks.

Dave