I am vehemently opposed to any sort of octothorpe reader syntax for
arrays; I have a preference for SRFI 10.  Indeed, SRFI 4's various new
octothorpe reader macros caused much of the motivation behind SRFI 10.
I instead propose that various SRFI 10 octothorpe-comma constructors
be defined, perhaps as #,(array {vector,ac64,...} [rank]), or perhaps
as #,({vector,ac64,...} [rank]); either way, I'd _much_ prefer SRFI 10
constructors to new #Afoo stuff.

If this is intended to be the _basis_ for array manipulation, will
there be a follow-up of a complete array library to deprecate SRFI 43
and some of 13?  (I say 'some of' because there are still many useful
string-specific routines in SRFI 13 that it would be nice to keep.)

ARRAY=? is less general than it could be.  I'd prefer an ARRAY= with
the same sort of interface as LIST= from SRFI 1 and VECTOR= from SRFI
43, respectively.