I wondered about this. I would sincerely hope that the permissions list is already priority-sorted somehow; otherwise, it’d be trivial to just list five innocuous permissions first and then put the dangerous ones later. Even with scrollbars, most users would just see the first few and likely not bother to scroll down at all. Note that in the author’s post, one of the dangerous permissions (read and modify data for all websites) is already listed in the box.

Have users view and approve each permission individually. First permission is listed, buttons for "deny" and "approve", user clicks "approve", next permission is listed, etc. Clicking stuff is a lot of work for users and some of those permissions sound pretty intimidating, so I suspect either extensions would start getting by using fewer permissions or users would start getting by using fewer extensions.