Making UI interactions bufferable has appeal to me as well.

I had a similar thought but just for the more conventional 'keyboard shortcuts are not discoverable' problem.

Using the status bar or an overlay showing on-screen-keyboard shortcuts, the app could give visual feedback every time you click a button or slide a widget revealing what keyboard shortcut would have triggered that same action.

I click the "GO" button: OSK overlay or status bar shows [GO] (Ctrl+G)

I slide a widget to turn volume up: status bar shows [Volume 22->37] (Alt+V,22)