I have seen some white papers, Cairngorm V2 is not always good to use for flex framework. so many flex projects are converted cairngorm 2 to cairngorm 3.
What i guess is what ever cairngorm 3 is developed based on the cairngorm 2 framework.
So why all the projects converted to cairngorm 3 because of some issues in cairngorm 2 while using large flex applications.
thanks,
ravi