Via Neuroskeptic, I just found out that the Big Five have been proposed to appear (sorta) in the DSM-5.
The current Axis II disorders will be replaced by a mixture of continuously-rated personality disorder types (carrying forward psychopathy, avoidant, borderline, obsessive-compulsive, and schizotypal) and 6 personality traits. According to the rationale, four of the traits are pathological versions of 4 of the Big Five (Openness/Intellect apparently doesn’t have a pathological extreme).
I need to read more about it, but it’s not clear to me how redundant the types and traits will be, and whether that’s by design. For example, the typology includes a schizitypal type, and the trait space includes a schizotypy dimension (the latter based on David Watson’s work suggesting that trait terms referring to oddness/eccentricity should not have been excluded from the lexical sampling that produced the Big Five). Both are continuously rated — will they provide complementary information, or will they just say the same thing?
One good thing, though, is the shift toward using continuous ratings rather than yes/no categories. This will potentially create practical problem for the healthcare system (if something is continuous, at what point do you decide that insurance will reimburse treatment?), but scientifically it is better in line with what we know about the underlying nature of personality and personality disorders.
The Hardest Science 