I am assuming that Rydia decided to come back to the real world after staying in the World of Phantom Beasts. Maybe she realized that she would die an early death and that she should have been back at the Village of Mist to train the few survivors that were left, or maybe it is a reference to her ageless nature because every character, if I recall correctly, had an, at least, somewhat assumed or given age in promotional materials except for Rydia after her reappearance.

I think that the new designs are very interesting and I hope that Square Enix considers a port of some kind to a medium that players outside of Japan can enjoy. I know that Square Enix realizes that they alienate players outside of Japan when they decide to release mobile games, but they must consider it a better marketing move if they can increase their sales in Japan in the short term rather than market it worldwide in the long term.