I would like to discuss the differences and similarities I see between their work and my perspective; are you are familiar enough with STEPS to discuss it from their point of view?

I think I am (though I'm but an outsider). However, I can't really see any significant difference between their approach and yours. Except maybe that their DSLs tend to be much more Turing complete than what you would like. It makes little matter however, because the cost of implementing a DSL is so low that there is little danger of being trapped in a Turing tar-pit. (To give you an idea, implementing Javascript on top of their stack takes 200 lines. And I believe the whole language stack implements itself in about 1000 lines .)

In the unlikely case you haven't already, you may want to check out their other papers, which include the other progress reports, and other specific findings. You should be most interested by Ian Piumarta's work on maru, and Alessandro Warth's on OMeta, which can be examined separately.