But what is the 'lexically obvious object' for symbols in a macro expansion?
(= z '(list y))
(with (x 1 y 2)
(mac foo () z))
(with (x 3 y 4)
(pr (list x)
(pr (foo)))
which expands to
(with (x 3 y 4)
(pr (list x)
(pr (list y)))
To my mind, the lexically obvious value of y is 4 in that last expression, just as the lexically obvious value of x is 3. I see nothing lexically obvious about giving y the value 2, because there is no lexical reference to y in that scope.
So in my opinion, lexical scoping and unhygenic macros are both doing the lexically obvious thing. Hygenic macros introduce a whole new kind of scoping that is neither lexical nor dynamic, but looks like lexical scoping in specific circumstances.
Unhygenic macros preserve true lexical scoping while hygenic macros try to override it. So from my point of view, the question should be "If lexical scoping is a good idea, why would you want hygiene?"
