Plenty is doing.
"....what first attracts our attention is the consistent relationship (median .40 in 5 large samples) between Extraversion and Openness....as well as the negative relation (around -.40) between Neuroticism and Conscientiousness... ....if Openness could be seen as a - very important - facet of Extraversion, and Conscientiousness as an important component of the positive pole of Neuroticism; and if, conversely, as is well known, Agreeableness is a good marker of Psychoticism [5 refs], is the ghost of the P-E-N system not reappearing here...?"
Disclaimer: this quote appears here only to spark discussion. It is not endorsed one way or the other. Make up your own mind. Or just refresh the page for another viewpoint. From a collection assembled by the late Chris Brand.