If that is, indeed, the aim then I think it's a very good one!
That's terrible!! You don't always have everyone in a group that wants to play each role. People want to play what they want to play, not what they have to play. Also, if they continue down this road then the least amount of player's needed in order to play is 4, one for each role.
The purpose of the classes having secondary roles was to be able help pick up the slack if another role went down, or wasn't present at the game.