Sounds promising. The trouble is that programming-as-teaching relies on a fairly rich set of runtime language features. The language runtime has to know a bunch

Sounds promising. The trouble is that programming-as-teaching relies on a fairly rich set of runtime language features. The language runtime has to know a bunch of stuff about what's in memory in order to provide the programming-as-teaching features. That makes it hard to add the needed features as bolt-on extensions. You sort of need the whole environment to be designed for that kind of work from the ground up. So if you're right that programming-as-teaching, and image-based development, is a good solution to the issues you face, then an old-fashioned Smalltalk or Lisp system seems like a good choice. If you want those features, but you don't want Lisp or Smalltalk, then I think your only option is to build a new development environment for your language of choice that has the requisite support. That's a tall order. Sometimes I've idly toyed with the idea of writing a Ruby implementation on top of a Common Lisp or Smalltalk runtime, but that would be a huge amount of work with no guarantee that there's any demand for it.