Bi Dhikri Allah, you may already know this, but in case you don't, I think the majority of people who could answer this from a Jewish perspective are away.
I might be wrong about that, in which case,, and my apologies.
Good question. You might have to wait for the reply, but I am almost certain that you will receive an informed one in the future.
Just wanted to let you know, as you have been helpful to me on other boards.
basically, he's very important, as without him and the men of the "great assembly", the chain of authority and transmission of the Torah would have been broken in between the first and second Temples. have a read of the first entry here: