One may not like Deleuze's system, but I don't think it's fair to call him a charlatan. His work on other philosophers (e.g. Leibniz) is highly regarded, he provided valuable counterpoints to Freud, and Badiou accused him of being a secret platonist, which I think most hn-posters would appreciate. His one-off observations alone should be enough to grant him the benefit of the doubt. If you don't recognize sparks of brilliance in his lectures and conversations, well! See the abecediary, or his lecture on cinema as the creative act, or any of his readings of past philosophers.