I still know of a few very popular community members who have yet to reveal who they are. I think it takes a lot to get to that level, but it is possible. Being a great developer helps a lot and just proving yourself over and over makes it hard to ignore that person. I think having anonymous witnesses for instance can be a good/bad thing. It is great for nobody to know who to go after if they wish to try another hostile takeover. However, it could be a concern that if a potential witness did something bad, we'd never know who it was.
Tough to say what is the best choice for each individual person.
Revealing themselves can earn more the trust of the community, otherwise they will lose their image and it could be a turmoil.