What I should have asked is, what are ESRI's plans re: ArcObjects and exposing is full functionality via other APIs/SDKs? I feel like the waters have been muddied in the last couple years and, although the range of tools for building add-ins has increased, the capabilities have taken a step backward.
One of these tools used daily is Tail Swapper. It makes it possible to change the type of aircraft swiftly if there is a change in the number of passengers. It helps avoid flights being operated with an unnecessarily large aircraft and save fuel accordingly.