Bad medical or legal advice is completely possible. It exists now.

Giving good medical or legal advice requires, at a minimum, being able to carry out a full conversation to investigate the problem, including understanding things not directly related to the field. There's no sign of getting that any time soon.

Efficiency improvements in an area like the law may also result in people imposing new burdens, eroding the efficiency gains. Laws that once would have seemed too burdensome will no longer be seen as such.