[plt-scheme] keywords (a possible alternative?)

Personally I dislike colon prefix keywords, as to me colons tend to imply
an association between elements, therefore a postfix positioning seems most
visually natural (but of course subject to the same incompatibilities).

However, wonder if something along the line of:

 (function (: keyword expression) ...)

Might be both more syntactically consistent with the language; and enable
keywords to be bound to argument expression lists, which a pre/post-fixed
keyword association couldn't syntactically naturally support.

 (function (: keyword expression ...) ...)

As just a thought ???