Oh, well if they didn't charge monthly then sure, I would be for it.
I want to play the Old Republic that is coming on the 20th so bad, but am not willing to be continuously milked for my money
At $15 a month, I'd say it probably pays for dedicated servers, as well as continuous patches and updates. It depends on the amount of content and quality of the game, however.
So far, it looks like TOR could get away with the monthly fee, for all of it's supposed size. I mean, they've said there are multiple, huge worlds. It might have something going for it, but it's still up in the air.
On the other hand, a game like GW2, in which they have no monthly fees, is an obvious steal. Dedicated servers, online play, a massive world, the content REQUIRED by an MMO, for the same price as CoD. What GW2 will lose in sub fees, it makes up for in sheer amount of units sold, as well as the rate at which Arena.net pumps out new expansions.
So, it really depends on the developers plans, and the way it will be worked out if a TES MMO goes into production. If they're going to rely on content and expansions to sell it, it may be worth the price tag. But, as I said, it would cost too much time and money to be a smart investment.