Yea, don't have a phone that can play it (and honestly also not the free time at hand), so I follow solely the story cutscenes in order to keep up with the developments.
Well, Eph already got more than several other of the KH original characters got.
When one compares his initial self from Browser-chi (which is Japan only) where he's just an inquisitive, curious and friendly kid who has to stick his nose everywhere and is trying to decipher the truth behind the Book of Prophecies and the weird events in the world, to the rather insecure grand leader-figure with huge responsibility pushed upon him there is certainly a difference in outlook.
The story of Union Cross also just started and as its looks like he's going to develop some closer ties with both Skuld and Ventus, so the potential for more is certainly there.