The Cocoa APIs basically simply ask the developer to fill out a form when they’re asked to do so. I’m not sure how much more higher level and abstracted one can

The Cocoa APIs basically simply ask the developer to fill out a form when they’re asked to do so. I’m not sure how much more higher level and abstracted one can get without relinquishing control of how the data is displayed. It's been successfully achieved with Convention Over Configuration. See MacRuby's HotCocoa.