I agree with Les on this (hey Les, how's things up in Saskatchewan?)

The braces are part of the frame. I personally don't believe in relying on sheathing to brace or provide stiffness. My own personal philosophy is to make bracing very redundant, for the simple fact that Roger points out so well, you don't know what's going to happen a few decades down the road.

A timber frame is designed like it is for a reason, and I'm sure Time knows this very well.