On some sort of longish timescale, you want to remove the ability to access ohai data via the flat namespace. See @stevendanna's examples, and the newbie toe stub example I gave in response to Lamont. To be clear, I'm advocating for introducing a warning in Chef 12, and removal in Chef 13 (or longer, if 13.0 comes out too soon after 12.0). No one will be broken immediately.