I am a lawyer, and advocate for the diocisan tribunal and a deacon, so maybe I can speak to your question. Most diocese are in need of people with legal backgrounds. The annulment process is time, personell and asset consuming. So are social issues that often require a legal mind to fully analyze. Your legal training would definitely, IMHO, greatly benefit you in the priesthood, and your diocese. Often, if given the opportunity and the resources, a diocese will send a seminarian with a law degree to Rome to obtain a degree in canon law. Compared to law school, canon law preparation is pretty easy, especially if you have a civil law degree already.
HOWEVER, I think you need to seriously consider WHY you feel the call to the priesthood. If you discern a calling to be a parish vicar or pastor, the legal degree, although still helpful in that role, may lead your bishop to place you in an adminstrative role, where any calling and desire to serve in the parish would not be fulfulled.
By the way, contrary to popular opinion, being a lawyer and leading a holy life are not inconsistent. :D
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