I prefer the option to pay as I go model, so if I am playing the game a lot one month maybe I can acquire a lot influence and get new content, but if I have a busy month and can't play as much, I won't be hit with the 15/ monthly fee for a game I don't play (I'm looking at you WoW!)
From what I can tell the way they plan on setting it up is about as good as it can get with being fair to all players as much as possible. I guess what it will come down to is if the extra content is worth the cost in money or influence.
In the end you can still play this game without being forced to pay a monthly fee. If you like the game, you can spend 5,10,15 bucks a month on extras. I don't really see that as a negative.
I found Rome of clay; I leave it to you of marble - Augustus