This is how higher education was done for literal centuries before moving to the written word. So it’s not exactly innovative to return to oral arguments. But what it does threaten to do is effectively abandon all the efficiencies of the written word. When higher education evolved into a mass system in the 1800s and into the 1900s, pure oral examination was looked at as super inefficient. A written paper could be han…
You don't need to do everything orally. A return to handwritten final exams done without electronic aids would help too. They can be open note as mine were in the mid 70s or even open book.
As for scalability, I really don't see the problem; if we are producing so many qualified people then we surely can use some of them to examine the next generation. It sounds like the argument that often appears on the web where someone, usually an American, claims that a solution that works in, say the UK, can't work in their country simply because their population is larger.
Also, we really should consider if shoe horning every young person into an academic institution is useful either to society or to the person concerned. It certainly has not been an unmixed success in the UK.