Besides borderline the other personality disorders are a lot harder to treat because many of them don't want to change. If there is no will, than there is no way. So I would have to agree, you cannot do a personality transplant (unfortunately). Those who are Bipolar are not as crazy as they are portrayed in the media, most people I know with bipolar are doing better than I am in life right now. Many people with personality disorders do not even know that their behavior is problematic, because it is so engrained into their personality. It is only with psychoeducation that people with personality disorders begin to realize they are disordered. Only after this realization that changes can be made, the younger, more intelligent the patient the better the prognosis.

Personality disorders share many things in common, one of them is a history of trauma during their most formative years. The effects of trauma in childhood cause brain damage and impair functioning of the brain including the prefrontal cortex, the part of the brain involved in reasoning. Also the Amygdala, the part of the brain the processes emotional reactions. Which would explain why my emotional reactions are usually delayed when I am presented with triggering stimuli. What we are attempting to do in treatment is repair what is according to the scientific evidence a damaged brain. There is much more work involved in repairing a damaged brain than there is in correcting a chemical imbalance. Source: Scans Show Brain Damage in Abused Teens
Brain and Development affected after Child Abuse | Mind Forums

Sadly many parents are not aware that they are abusing their children, they are simply using the same twisted and broken techniques taught to them by their dysfunctional parents.