You don't have to use the Quicklisp client to load dependencies, just to fetch them (as a package manager). And for that, I think it should be always used this way.
I work on multiple projects which do not use Quicklisp at all, for a variety of reasons which are not worth going into here, but which are unavoidable. And I work on other projects which use Quicklisp for some dependencies, but have other dependencies which cannot be in Quicklisp, again for a variety of reasons.
Using one of the Quicklisp monthly distributions as a base does not preclude one from having local dependencies.
-- Stelian Ionescu