Today I found a way to assert that an edit form's inputs include a record's saved data. I think it strikes a good balance between broad and narrow scope.
# spec/features/user_edits_kit_spec.rb
within 'form' do
expect(page).to have_selector("input[value='Default copy.']")
end
This asserts that some content is inside an input field in the form, rather than just anywhere on the page. You can narrow the scope as needed.