I hadn’t thought much about canonical plugins before, that’s an interesting concept and something that makes sense.

Regardless of the drama around WP Engine and ACF, it always seemed to me that custom fields (and perhaps custom posts registration) would be great in core (including repeater fields!), it would quite possibly be very useful for many people and it’s often so much easier to manage with ACF (or similar plugins) than in your own plugin or functions file. But most likely my thinking is clouded by my own needs and preferences, as it’s something I generally always use when building sites!

What goes into core is an evolving process and sometimes big changes end up “make WordPress WordPress”. I had many arguments with people in the forums about custom post types, before they became part of core – something I strongly supported. Many made the argument that they didn’t belong in core, because WordPress was a blogging platform and not a CMS. If that change hadn’t happened, I think WordPress would have been the poorer for it.