Expert systems will be welcomed right up until the point where they start making the legal profession look incompetent. Vide what happened with MYCIN in the medical community if you need a refresher course on how this is going to go down.
Maybe the new generation of young lawyers will be running virtual firms this way and serving a much higher volume of clients for cheaper. There is a huge untapped market of those who need services for black letter issues but can't afford it.