The logical question that the Classic team and likely Blizz at large is asking themselves is: How do we keep Classic going? How do we keep it "evergreen" and sell this product over and over again with the least required expenditures?
Part of their answer is TBC Classic. So next is Wrath, Cata, Mists? Servers for every past expansion? Who knows how feasible that is.
Let's take a look at three examples:
- Skyrim (and Fallout)
- Minecraft
- Warcraft 3
What do these three games have in common that they're best known for? The modding community. As it turns out, video game player bases often hold within them untapped creative potential, sleeping engines of creativity that only go noticed on forums. Creative people love to create things, especially when they're inspired by something they love. All three of the aforementioned games have retained their player bases over the years because they gave their players the power to express that creativity. They let us mess with the files and now all sorts of awesomeness has made the games better than they ever would have been...
I think you know where this is going. The WoW fan base holds an absolutely massive creative engine that we see in every damn form of media out there. Thus I extend to you the notion of the "World of Warcraft: World Editor." Give us the keys to the city, Blizzard, and the city will last forever.