I actually think Willis is the more interesting appointment. Willis' aerodynamic expertise and confidence is just massive. He was the man with Williams (worked with Newey) in the early 90s during their dominance and he was the point man for Adrian Newey with Red Bull through 2009. No one really knows why he left RB but anyone can fairly say he had his hands all over RB6 and helped make it what it was, which was of course very dominant. If anyone asked me why he left RB in '09, it would be because there were too many cooks in the kitchen. Just my opinion. Looks like Brawn is putting together another all-star team. This is very similar to when Didi gave Newey carte blanche to build the team. These actions reflect Dr Z and the board giving the same kind of authority to Brawn. Build, win, win, and win some more.
Costa's Ferrari departure was rumored to be more politics than a lack of ability on his part. Lots of friction inside Ferrari with two years of mediocre performance.
It was typical Ferrari doing Ferrari business which is very impatient and political. They will hopefully learn from this when MB and Costa wipe the field with them. I fear for Ferrari's loose-cannon ways.