Basically it would be just to redo the race and traits of your current character not to change your class. My idea is for it to be offered in the c-store. A lot has changed in the game since launch. New races have been added powers have changed. Players have built characters to do one thing and now they want them to do something else. Maybe they just wished they had chose another race. Or they have learned more about the game now and made mistakes making their character.
There could be a time limit on it so if you used the re-customization you could use it again for a month. With accolades coming out so much would be lost by making a new character. Some would never re-roll but would like to change their race or traits. This would be another way for players to love their characters and improve their gaming experience.