Here's my opinion on the matter (and anyone sending an email to Scarlet City Studios can include this):
I have heard of other MMOs like Star Wars: The Old Republic having a subscription-based account, but then switching to a free-to-play mode and earning three times as much money. SWTOR is, of course, has in-app purchases, and that is how all of the extra money is made. Having a cheaper game would make more people want to play, and those people would pay more to play the game.
And the point of making a Christian game is so that many people will play it.
But I also know that SCS needs money to make more of the game, so a price increase would probably have to come from somewhere. This could be either a larger up-front cost or a recurring cost. I have heard other forumers say that an individual might spend less money if the game switches to a subscription, and I'm sure that a far smaller number of people would be inclined to pay monthly. I myself would be hard pressed to keep up a subscription. What would that mean? Would I not be able to play the Aetherlight anymore? I would be very sad about that. A constant drain on money is a big deal, almost certainly a cutoff point for a multitude of families.
So, I believe that increasing the purchase price of individual updates would be cheaper for each individual family, get more money for Scarlet City Studios, and allow a lot more people to experience playing the Aetherlight. To me, that option seems like a clear win in every way.