Not just a clown, but a Flanderized clown in a 'funhouse mirror' (to use Randy's term) version of the world that was mainly targeted towards 13-14 year old boys (towards whom he admitted to aiming the DNF game at.)
That game was shit not only because he aimed it mostly at the wrong age group, he failed to grasp that in DN3D the porny stuff was not even a huge part of the game (kicking alien ass was) and what there was, was a lot more mature and tasteful and not some prurient sex jokes intended to impress some adolescent boys. Also Duke's one liners and jokes only really shine when the world he's saying them in is serious. Having most of the NCPs also acting like horny dumbasses in a 'funhouse mirror world' is cringy and not funny and makes Duke look retarded.
That's how badly he misunderstood the games, and if he made a movie, it would definitely crash, burn, and leave radioactive fallout. Some of the older fans that played DN3D pretty much walked away from the fandom after DNF dropped, and what was left was either long-suffering normies that went quietly back to the older games or those weirdos overly obsessed with DNF's digital titties. I can understand however why some people walked away, DNF all but glassed the planet, and made everything related to it into a joke that was long past it's prime.