I don't think it will do much of anything. Organized crime has been going on in Italy for more than a century, and maybe longer than that.

People involved in organized crime are not going to lose sleep over the threat of being "excommunicated". Plus it's not as though people involved in that line of work run around holding signs, or tell everyone even priests.

How about excommunicating child molesting priests, cardinals, bishops, former popes throughout history, and putting the ones that are still alive in prison where they belong?