At a glance, that looks a lot like that Syntactic Closures model: Modeling the environment as both mappings between variables and values, and identifiers and variables. However, I fail to see how renaming is problematic in recursive macros, save being unweildy. I'm not sure, but AFAICT, this may be a solution in search of a problem. It is interesting though, and might be an actual better solution. It's hard for me to tell without a long, slow readthrough, which may happen later.

But this is just a concrete instance of my opinion of Racket in a nutshell: Cool ideas, but sometimes overly complex for my liking, interesting systems that don't always mix well, a syntax over the ideas that I find distasteful on occasion, and documentation that is comprehensive, but hard to understand.

It's okay if you like it, and it's a good language for Getting S%#! Done, but it's not really my thing: I prefer Chicken: Simpler, less academic and cutting edge, but still really good at Getting S%#! Done. But that's my problem, not Racket's