I think first and formost everyone is forgeting that the Mountain Circuit is a public road for most of the year. The authoritys will have no hesitation whatsover in altering any part of the course on the ground of safty for the genral public if they though it is feasable and cost effective.
For me, you only have to look at the changes to the run into Govenors to see that. which is effectively a by-pass now. ( although in fairness, the changes there were more to do with increasing the traffic flow at peak times)
The changes to Windy and Brandish have just allowed the trafic to travel at a higher speed around them more safely, but in the case of Brandish, I dont see the point.