I still think core functionality shouldn't be put into plugins in any software system. You should have sane functionality and defaults right out of the gate. Plugins or modifications are for extending the base use case. Configuring your software to me is a base use case.
What they did instead was to move most of the core functionality in plugins maintained by the core contributors, so they're plugins all but in name. I.e. they can be installed separately, uninstalled, etc., but about 100 plugins are supposed to be used together and you see them frequently in examples, docs, etc.
That "about 100 plugins are supposed to be used together" is indicative of bad design to me.
They really should be taking a look at modern systems like Concourse CI to see what they can do to improve.