Problems with the U.S., U.K., Canadian or any other justice system are irrelevant to whether or not Amanda Knox and Raffaele Sollecito were wrongfully convicted. Anyone, from anywhere, has the right and, in my opinion, the obligation to speak out against injustice wherever and whenever it occurs. It scares me more that it appears there may be people in Italy, the U.K., and other places who fear to speak out because of fear of reprisal by the "Guilters" or the "System." If that is so, that is a parallel with the worst systems in the world (like Iran and N. Korea, for example.)
I hope the Italian people and government can see this and will accept what is said in the right spirit. I don't think they want to be like the countries I mention. The Italian government was highly critical of George W. Bush and the State of Texas for the execution of Karla Faye Tucker more than two decades ago, and rightly so in my opinion. I hope they realize that many of us accepted and welcomed their views at the time.
Most justice systems, including the Italian one, are basically good. All have aspects that could be improved. The biggest criticism I have of the Italian system is that it seems to be a criminal act to criticize their police, prosecutors or court. No system of any kind will ever get any better if honest, fair criticism is stifled.
The big problem with any justice system is with the people who operate it. If they lose objectivity, people suffer unnecessarily. Surely most police and prosecutors see that the way they conduct themselves reflects on them and their country, state, and profession. If they act in a way which is clearly fair, convictions will be accepted and justice is the likely result. If not, they bring their justice system and their whole country into disrepute in the eyes of fair minded people throughout the world. This is why there are overriding legislative pronouncements like constitutions, bills of rights, etc. There must be a means of redress where public officials go rogue.