If I had to bet on what is going to happen to ESO at launch it would be this:
It is going to meet less to barely equal its expected sales, mostly due to the subscription model. History has shown, that players do not care about what is offered for the extra money, they will not buy the game if they have to pay monthly. Only WoW has been able to accomplish this. After launch the number of players is going to decrease as months go on and at around 6 months - year period it is going to go free to play. If Swtor has shown anything that going free-to-play is pretty much going to save the game from complete failure. So if you don't want to pay the subscription, history has shown that all you have to do is wait. PS4 not requiring plus to play the game might help a bit, but no were near enough if Microsoft doesn't follow suit. In all I think the game isn't going to be a success on console and that most of the business is going to come from PC. I understand the developers want to have a successful game, but they are going about it the wrong and, more then likely, the subscription model is going to have the opposite effect that they want.
Oh and on top of that, the impressions of the game so far have been pretty negative, which also may hold the game back considerably.