1. Of course Tradition can come to be expressed in writing ... but that writing is always secondary to the living Tradition as it is experienced. So that writing down becomes like a snapshot moment, whereas Tradition is more like a movie that is still running.
2. The biggest error about the Catechism was the muddle about who the intended reader is. The original idea was that it be a compendium for bishops to guide their own catechetical work. This became conflated into a book for every Catholic ... but without any adjustment for the difference in theological reading level.