Very interesting! My understanding is that you're thinking about this more in terms of an 'application environment for power-users' than in terms of a 'multi-faceted IDE with lensing'.

To clarify, the specificity of Emacs is that it fully exposes it's internal function sets to the world. This could be done by other applications in an organized way. For example, in the picture-editing app example, it would amount to allowing scripting over the features that the app exposes. The scripting feature would come from the environment, not from anything specific the app itself does (apart from being built in that environment). The previously mentioned IDE could then be thought of simply the multi-tasking environment in which such generic applications are running.

Does this roughly correspond to what the project is about?