This is a topic I can see both sides.
In principle, I support subscriptions for MMO's. Continued development and expense paid for fairly as the best and fairest model, over crippling features to re-sell the player with a 'free to pay' mode as I call it. But the market has spoken and many players pick the 'free to pay' over the subscription even if they complain about the harm to the game that design causes.
So I have some sympathy for games trying to find a way to make subscriptions work in this market and how hard that is.
Having said all that, I wanted to play and enjoy ESO casually, not have a subscription game. It's better than I expected and I've played quite a bit.
On the subscription, ESO has seemed to find a pretty persuasive angle of holding inventory hostage as pressure to subscribe - with lots of icing on the cake if you do. The 'crown' model seems especially well designed at making it easier to swallow.
But most players I've seen answer the question why to subscribe answer the crafting bag - i.e., a functional inventory system. So on the one hand, I'm glad to see something to get subscriptions, on the other there's something I just don't care for about having a practically unplayable game because of an intentionally designed inventory problem, unless you limit loot a lot.
The game - and I this is mostly insidious, with a slight aspect of a compliment to the word - has really added the pressure on this inventory. Things to gather everywhere, with hundreds of items, in every land, in every dungeon, in crafting rewards, all of which is a nightmare without a crafting bag and automatically handled with one.
I tried playing without a subscription and it was pretty crazy - it felt like half my time was on inventory. When I'd do daily writs, for each one, I could be selling items to the merchant temporarily to make room, running to the bank to store the rewards, etc.
Before I began playing ESO, I asked one question in a forum, 'can the game be played ok on inventory without the subscription', and was told yes. I think I was wrongly answered, unless as I said, you don't want to craft or collect large amounts of items you are handed.
Where I'm heading with this is to say, it seems like they're playing a dangerous game, by making the game almost unplayable without a subscription if you want to get much of that loot, driving players to be more likely to just quit playing - which might make some financial short-term sense in a buy-to-play, but doesn't help the product long-term.
But on the other hand, where would it be with a low subscription rate. So there are no easy answers. I'm both disliking the design and seeing ways it is well done and sympathetic to the need.
It would be easier if the marketplace had subscriptions as a standard, and ESO just had to compete with other subscription MMO's. It's a great game and would do well. But its competition is a lot of free to pay high-grind games that unfortunately get a lot of players.