IMO way too Expensive. I wouldn't have played either Skyrim or Oblivion for 15/month. I can't imagine enjoying ESO more than Skyrim or Oblivion, therefore ESO does not warrant more than what I paid for a single player game.
Either a buy-single fee of 40-80 or a monthly fee of 5-7/month would seem more logical and would attract more people.
Also a hybrid paying system where ESO PVE = single fee 40-80 with an additional fee for PVP.
As was announced, 15/month VERY risky!
After I heard about paying 15 dollars each month for the Elder Scrolls Online I was wayyyy against it. That's 180 dollars a year! A true Elder Scrolls game is a singular pay only! You think that after seeing the success of a game like Guild Wars with a one pay fee, Zenimax would do also. In this harsh economy that we live in, Zenimax should let the players only have to pay one fee! There goes my ESO dreams...