I said other, for what I loved the most of all....
Character relationships.
Other characters, NPCs or relevant characters, mentioning others
Family
Mentoring
Friendship
There was so much character development in these games. Wally grew from a timid young boy to a strong and capable trainer thanks to you. Steven is mentioned for no reason by characters like the fossil maniac, Roxanne, Wallace, at least two random NPCs etc. Norman is a lot more fatherly. We got a cute scene between Steven and his dad. Brendan/May were a lot more fleshed out as both friends and rivals. Zinnia was perfectly written to be a character with a strong bond with one who had died. It just felt like everyone was connected, instead of just being, well, characters.
Oh and delta ep was second just for the epic. The minor origin-platonic bits. The Zinnia. The intensity. The spaaaaace. So cool.
Third was that the Steven encounter on route 118 was actually relevant. Just loved that scene :3