If cplx-fun is a macro rather than a function, this doesn't work in arc or anarki at the moment, but I consider this a bug (it's fairly easy to fix, though) - if a symbol evaluating to an object is valid in functional position, the object itself (if it evaluates to itself) should be valid as well.
Of course, what's really needed to solve this problem is hygienic macros. I think, however, that it's probably possible to implement hygienic macros or something close enough in Arc without adding any axioms.
