We cannot look into the future, but if R7RS-large becomes at least as
powerful in the macro department, we may even be able to make SRFI
177's syntax to be as nice as the existing native systems.
I think we can maximize the chance of getting syntax-case accepted in R7RS-large if we can get it ported to Chicken, MIT, and Gauche, the three major holdouts against it. Without two out of three I don't think it'll fly; even if it passes legalistically, not being able to port to those platforms is a big barrier.
There's no way I can do this work myself, but I think it has to be done, presumably with concomitant modifications to the native explicit-renaming systems on those platforms. MIT has syntactic-closures, which may be a better base; it should be straightforward to see if the Chibi version Just Works. Did you have to patch Chibi to make your library work there?
IFirst of all, `define-syntax' has to accept transformers that are just
a procedure taking a single argument (the form that is to be
transformed). In this modified system, the original transformers like
`er-macro-transformer' become forms evaluated at compile time that
evaluate to such single argument procedures.
Chicken definitely cannot do this. Although er- and ir-macro-transformer are procedures, they return opaque transformer objects that are not procedures, and (define-syntax foo (lambda ...)) fails with a dynamic type error "transformer expected but got procedure".
All of these changes/additions are not particularly hard to implement
in a working `er-macro-transformer' system. Except for psychological
reasons, I don't see a barrier.
The psychological when projected outwards becomes the political.