The identity-concealing uniforms of riot police are both a psychological move and a move to protect their identity. Expect some police to start customizing their gear by plastering decals indicating the number of successful baton clubbings. Think of all those jerks with sports cars and tinted windows. Notice how they drive. I tend to side with the cops on this one.
Cops get out on the line against rock-throwing assholes, they have to be protected.
Two - anonymity, which is really another form of protection for cops. So they and their families don't end up sleeping with the fishes two days after their faces end up on the news. A riot cops identity should be protected. Of course, that does not mean that they should be anonymous. We could set up some sort of system where all the riot cops have easily identifiable markings on them.