[theoh]

I think Deleuze (who described some of his work as belonging to the genre of "generalized anti-Hegelianism", which I take to mean a kind of inversion of Hegel, i.e. a materialism) would just have laughed if you said his ideas were iffy. It's part and parcel of being on the radical cutting edge "producing concepts" in the philosophical tradition (participation in which necessitates acknowledging Hegel).

Is there a philosopher whose significant ideas were not steps into the unknown, moving beyond accepted thought? No philosophical idea worth considering is incontestable.