The Eorzean font isn't too hard to read, it's not even a substitution cypher but just a stylized script with a couple of letters reversed or altered. As Vespar said, it's part of the worldbuilding of the game.

Personally I far prefer the Eorzean script over the horrible Cocoon/Pulse scripts in FFXIII as they truly were totally unreadable without a key (that was included with the strategy guide book no less!), no wonder SE just scrapped the whole thing and went with Roman letters/English for signs and the like in Lightning Returns as it was just too unwieldy by that stage.