Designer personalities are possessed by people who are creative, and have the talent or skill of being innovative. According to the big five personality theory, people who are creative have personality qualities which are helpful in making something new, they take the initiative to create new things.
Designer personality is a term that has its basis in the genetic engineering enterprise in bio-medial field.
Even when it will be possible to 'create' a designer personality, it will be highly unlikely that an absolutely desired designed personality will be brought into existence, as we have not fully known the potential unpredictability within our species.
Advantage of designer personality can be this that it will be controllable, since it is programmed and predictable.
Disadvantage: race in designing humans and in engineering humans.