Agree with the sentiment, but at the same time understand the rationale - FFI implies alot of GC/memory internal interfacing stuff, and to some extent expects a c-based implementation (not e.g. JVM,CLR,etc).
If r7 & library interface are widely adopted, some flavors of FFI could evolve within the library/srfi process and gradually become defacto standards..
Probably hoping too much.. but in any event..