Re: Separation of Concerns
There is a story in one of Tom Peters's "Excellence" books about a new missile project. Three companies were working to bring together their separate developments. The critical interface was specified to be sufficiently loose that there was room to adjust the mating at the integration stage.
When Object Programming started to be mandatory it was found that projects could seriously fail if they didn't fully understand the application first. The structure of objects worked well for development - but required major redevelopment if the overall model proved to be incorrect in the real world use of the final application.