This is hogwash. Sure, you can "defend" the subscription fee, but why do you need to? Its been evident that the 15$ a month fee is to fund further development, EQ did it, WoW did it, every MMO thats even been released had this model at one time or another. Sure there are a few that come out F2P instantly, or B2P, but they fund themselves via sales of the product and the in-game store stuff.
Here's whats wrong with ESO:
60$ for the Box, or more of you get the Imperial Edition. Includes a free month.
15$ per month to continue playing after the first month, usually you have to register a payment method initially anyway and then opt out of actually paying further, otherwise they usually automatically bill you even if you stopped after that month.
In-game store. No, this is a bad idea. For one its not necessary, you cannot offer convinience, like leveling faster when you already pay a monthly sub to begin with. You also cannot sell luxury stuff like store-exclusive vanity clothing when by default everything IS paid for by the subscription unless said subscription automatically includes points or whatever you can spend in the store on top, see LOTRO for an example.
Pre-order bonus. This is dumb. First why would the option to play any race in any faction be a pre-order incentive if the whole point was that the races dont get along and therefore fight? Either dont have it or make it standard by default. Further Imperials being exclusive to the Imperial Edition..this is dumb again because this could actually be a simply pre-order bonus rather than being tied to the deluxe version.
And the biggest failure, your lore. Dominion makes somewhat sense. You can even argue the Covenant to a degree. Ebonheart does not make sense in any way. Nords HATE Dunmer, the only reason they ever worked together, which by the way was just a CEASE FIRE, was because of the akaviri invading. They would not work together, likewise the Dunmer have repeatedly waged war against the Argonians AND have enslaved a sizeable part of their population, they would under no circumstances work together.
It would be much easier if factions were instead split into 5. Altmer+Bosmer, Argonians+Khajit, Nords+Imperials, Redguard+Bretons and Dunmer+Orsimer. Or change the setup to Covenant being Nord, Redguard and Breton. Dominion being Altmer, Khajit and Argonians and Ebonheart being Dunmer, Orsimer and Bosmer. At least these races would have incentives and reasons to work together happily against the others, the only reason your factions are setup the way they are is because you were too lazy to actually stick to the lore and went with "their lands have to touch". Further Tamriel is tiny, if you want to make ALL of Tamriel playable, make each zone as big as a singleplayer experience, if you can play Skyrim for 80 Hours, then i should be able to spend 80 hours having fun in Skyrim in TESO. You can expand the game and its zones after you release the game, LOTRO being the example there, Rohan wasnt in from the start, neither was Moria, or Lothlorien or Mirkwood, these were added later on, with increased levelcaps and new content, you can equally limit the initial areas to ONE zone, such as High Rock or Hammerfell, Skyrim or Morrowind and Summerset or Valenwood depending on faction, then add the rest of the zones later, full of new content to keep players playing.
As it stands, this game is already a trainwreck and it hasnt even left the station yet. And if you think your IP is going to save you, Star Wars was a bigger IP, it didnt save SWTOR either.