How you looked at J. Paul Morrison's "Flow Based Programming" book? I recommend it since it touches upon a lot of similar topics. As your article points out, the concatenative style can be visualized as a flow; in the Morrison book flow is expanded upon with a more detailed, explicit connectivity system and an emphasis on visual language.

Regardless of syntax this is a very interesting language design space, since it seems to hold some of the most promise for lowering average software complexity.