Its a reason for people to do older content.
Want allied races? go can for the content.
Want t6 gear? go back to black temple
Want a nether drake mount? Go back to Shadowmoon Valley
Want a whatever? It is a recent to go back to that part of the game and play it. |
WoW's game design is based about keeping people playing, if they started just giving away stuff from older grinds than no one would ever go back and do the older stuff.