That wouldn't be great. It's cool to have old items be used again, making you go back and farm in old areas. It's necessary RPG element.
It's also great to get "prepared" for something like Challenge Modes. It puts you in a mindset that is helpful toward completing a goal.
Buying things straight from a vendor is not compelling gameplay to anyone. You might as well remove them from the game.
A hit! I've ran thru twice now with 9/9 gold on my lock and pally. The gear and mounts are cool. But IMO it's the most fun I've had in wow. Progressing with a 5 man group is much more personal than raiding. We became closer friends in wow and all of us got better at our classes.