New Pokemon Type
Real-time Battles
New Pokemon
New evolutions/pre-evoloutions
New/Returning Side Events
New evolutions could make some old pokemon really good. Imagine eviolite Shuckle
I'm hoping for a Dunsparce evolution and a male Gothorita evolution. Also, I'm pretty sure that we will see new evos (besides Sylveon) since gen 5 didn't have any.