In my opinion, I think the concept of ”storytelling” described in the article overlaps with an area of knowing that we have learnt previously, which is Language. Storytelling comes from language (which is a collection of written, spoken, and body language). Can storytelling exist without language? So, it cannot be a new way of knowing. And we can only see the positive examples. So, I cannot judge if “storytelling” is a way of knowing.
And I looked in the TOK text book (black one) page 70. There are some evidences that suggest we can think without language. For instance:
“We sometimes struggle to find the right words to express thoughts that feel as if they are already there. You have probably had the experience of saying something, and then adding in frustration ‘No, that’s not quite what I want to say’, and then trying to express yourself with greater clarity. This suggests that your thoughts are the prior to language and that we are simply trying to find the right words with which to express them”.
Thus, I think the generalization of “We cannot think without using metaphors” is not valid.