I remember they did say that Ar Nosurge was made to be a standalone game, so I guess it's not that much of a trouble. Also with the Ar tonelico knowledge I have I hope it won't be confusing. By the way, good news:
Tecmo Koei announces Ar Nosurge: Ode to an Unborn Star for PS3 in Europe!
Hopefully there won't be any DLC, since I can't buy digital content from EU.