Well, this game has a more ARPG battle format so it's going to naturally be a turnoff to some of the lovers of the FF series, so it's going to lessen some sales. Already seen some FF fans not be into this game and are waiting for World of Final Fantasy instead.

Though, on the other hand, it's going to bring newer fans into the series who might of been not into the FF series before.

Only the future has the answer.