As an economist, my area of expertise is less about how this needs to be specifically designed.
I actually respect your expertise in this area, Ms. Chatel, and Mr. Arnold is certainly an expert in this area.
What I know, as an economist, is that GAAR is incredibly out of date because the global economy has become much more digital, and the ability to shift intangible assets makes it so much easier to book profits in the most tax-favourable centre. The need to update it is long overdue, and I would absolutely defer to Mr. Arnold on what that could actually look like.