I think you have to consider some approaches and then go with the one that feels most natural to you. I lean towards writing, mostly because I keep myself more organized that way. When I talk in therapy, sometimes I go off on tangents.

I think it's very important to process past trauma. It's a way to free yourself of some or all. Then, it's good to work on leaving/putting such stuff behind you and to concentrate on the present and, to a lesser degree, the future. Being tortured (or torturing yourself) perpetually for past actions or experiences is wrong and self abusive, to a degree. I'm not saying the whole process is easy, but is necessary for a better life.