Players got their first taste of character re-customization way back when they introduced the paid name change feature. Then with patch 3.02, the patch that gave us the pre-expansion features like the new talents, more character re customization came in the form of the Barber Shop feature where players could get a "Shave and a Haircut" for a small amount of in game currency.
The new Character Re-Customization feature allows players to change all aspects of their character associated with cosmetics determined by that player's race and class and he can throw in a name change as well if desired. This means that the player can change everything about his/her character from skin color, face, to even that character's gender! This means that every aesthetic change is now available for players to change. It's not surprising though that changing the race and class is not allowed. Still though, this is a great step forward for players who are no longer pleased with his/her character's appearance and you get all that for a flat rate of $15 (minus applicable taxes).
Just like the paid name change before, the usual still applies. This is not a way to get off someone's ignore list. You will be updated on people's friends lists and all auctions and mail associated with that character before the change will still be directed to you. You can read the FAQ on this matter here.
This is a really nice feature to offer to allow players to really re-customize things about their character they want to change. The most surprising change for me is the fact that it allows gender changes. I actually rerolled my level 52 female undead warlock to a blood elf before since I didn't like the way undead females looked. If this feature was available back then, I might have considered using it to change to a male undead since that was fine with me. I'm sure a lot of players out there will find this feature pretty useful.