The early attempts at The Motion Picture are littered with "the full Gene," in all the worst ways one can imagine. In those later years, he really wasn't all that good of a solo writer; he needed co-writers and producers to keep him from going off the rails.He got humans so right in TOS but by the time TNG went into production he'd become a pretty eccentric and self-righteous (and inflexible) man who insisted that his vision of humanity was the only way to go. When a multi-breasted Deanna Troi isn't the dumbest thing 1980s Roddenberry came up with then you know it was a bad idea.