What's insubstantial about Lacan? There seems to be enough in there to give D&G, Zizek etc careers (as well as inspire a bunch of compelling media i.e. The Matrix)
All great things, but helping other philosophers have careers and inspiring cool art does not necessarily imply that you yourself had substantial philosophical concepts.
I'm aware: I was inviting your thoughts (this is a cramped space for a debate). For mine, reading Lacan directly is a chore (post-atom bomb academic arts can have a "use all the cool sciencey words" problem), but I find the Other/other and reworking of Freud's ego id etc thought-provoking.