Does every people group need a written Bible?

According to the ethnologue, there are 6912 living languages of which about 4400 have no Scripture available. About 3/4 of the world's population is considered non-literate, so how necessary is it for people to have a written Bible in their language? If you went into an unreached people group, would translating the Bible and literacy be your top priority like Wycliffe or would you use more of an oral approach to the Bible?

The International Orality Network as well as projects such as One Story focus on making sure that every people group has access to an oral Bible in their native tongue by the year 2020. An oral Bible is generally made up of 40 to 60 chronological Bible stories that are chosen based on the worldview of the people group being targeted. The stories are often recorded on audio devices and also passed around by word of mouth and oral tradition.

We read a book in our missionary training school called Making Disciples of Oral Learners which is a free download and a great introduction to orality and storytelling in the missions world. What do you think about sharing the gospel, making disciples, planting churches, and raising up leaders by telling stories from the Word rather than using a written Bible?