Entity framework 7 is planning on removing .edmx files from the next iteration. The migration over will probably be tough for people but they will end up with a much better solution if they start relying on the code first methodologies.

Luckily I started with EF 4.1 so I am very used to using code first on existing databases as well as new ones but this will be a giant leap for some developers that haven't updated their skills in the last couple of years.