In another comment above, pg wrote: "language A is better than language B if programs are shorter in A"

APL's terseness due to weird characters aside, since he did say that's not what he meant, APL can do A LOT by chaining a small count of operators together, which, to me, does seem to fit with the above quote rather well.

I would personally also suggest a Forth-derivative like Factor as another language that would meet the criteria of being small in parse-tree terms (and incidentally also in tokens).

As for what it would bring into Lisp.. I dunno. Maybe nothing :)