EDH stands for Elder Dragon Highlander, it's basically a multiplayer variant that has some deck building rules that make it more for casual play. It wasn't created by Wizards of the Coast, it was created by the community (it used to be called Commander), it was simply embraced by Wizards of the Coast and kind of made an official variant.
There are many great card games and certainly Destiny falls into that category, being number 10 in a top 10 list is not exactly failing. I would not expect however that at this point FFG changes its business model, my best guess would be that they will simply continue to develop the game as they have and simply reduce the production of the game to meet the expected demand, another words, sell to those that buy. This is at least historically their strategy with all of their games. In a sense this is good for casual players like me because it means the discounting of products will continue, making the whole game a whole lot cheaper to buy. Most stuff is already at 50% off in most places which I think may be sufficient to get more people to at least consider it.
Edited by BigKahuna