If you were Adrian Newey, would you go to Ferrari?
Andy Geering, via Twitter
Andy, Red Bull is a team that has been built up around Adrian's 'traditional' way of working. If he was to ask Ferrari's bosses to set him up like that, they might just think he was mad.
Drawing stuff in 2D with a pencil means you have to be able to understand it and by doing it this way you are not restricted by a CAD system's surfacing limitations.