The trick is that there is no actual definition of minimal, so you can always add it to your list of adjectives and sound more hip as a result. Another good one is "clean".
We try and help you keep it clean. Check out https://github.com/feathersjs/feathers-chat to see what our idea of an app should look like. Obviously, different strokes for different folks, but that's the kind of code we like.
Express claims to be a "Fast, unopinionated, minimalist web framework for Node.js" so we decided that minimal fits well because Feathers at it's core is just a very small extension to and in the spirit (or so we'd like to think ;) of Express.
The core product doesn't ship any of them, so you can choose the _one_ you need, or provide your own implementation by satisfying their well-designed service interface:
Out of the box is an appropriate way to describe it if it's a plugin that's been developed, tested, and guaranteed to work by the core team. Just because it's not installed/enabled by default is a good thing IMO.
All my code is bloated and messy, tbh.