I have occasionally found myself wanting to expand a macro in another.
Now, it wouldn't work to just write the macro I wish to expand in CPS
or as a syntax computation, because it needs to be an arbitrary macro.
I'm not _entirely_ sure if this is a good idea yet, but I think it may
be: I request that a SYNTAX-EXPAND (or whatever it be named) be added
to the current specification:

(SYNTAX-EXPAND <form>)                           ;syntactic computation
    Expand FORM completely and syntactically return the expanded form.

('Syntactically return' is probably not the right term, but whatever.)

It of course cannot be implemented as a regular syntactic computation,
so it needs lower-level macro system support.

Again, I haven't thought much about how good an idea this is, but it
has proven to be useful to me in the past.