I think Witt resists formal characterization, which is part of the point. But if you had to make it formal, the closest description would be that he’s doing descriptive grammar of epistemic practices, showing how words like know, doubt, and certain function and how philosophical problems arise when they’re removed from the language games that give them sense. But that doesn’t fully capture OC, because in OC he’s doing something more than grammar. He’s uncovering a structural feature of epistemic practices (I think it’s similar to what Godel did in math), i.e., that they rest on something non-epistemic. That’s a substantial philosophical claim, not just a grammatical observation. A purely therapeutic reading where Witt only dissolves confusions can’t account for OC, because the hinge concept looks an awful lot like a positive philosophical contribution. Which is exactly what my thread is treating it as.
This is probably why some philosophers refer to OC as the 3rd Wittgenstein (early, late, and OC).