Ars Technica - Breaking the lock- Why all game content should be unlocked from the outset.
The idea of locked content, which has to be "unlocked" through some sort of in-game achievement, is a peculiarity that games share with no other mass consumer art form. Books don't require you to read the prologue and author's note before diving in to Chapter 1. DVDs don't confirm that you fully comprehended the first act before letting you jump to your favorite scene in Act 2 (or make you suffer through the bad episodes of a TV show just to watch the good ones). Music albums don't require that you listen to songs in a certain order without the ability to skip around at will.

Forbes - Congratulations Ubisoft, You're The New EA. Thanks nin.