I think the multiplayer aspect is neat. After BW's entralink and the c-gear passerby features kind of bridging games together, and SWSH's wild area where you could see other people, now you can actually meet up and play the adventure in the same world. I wonder if they'll still have random trainers show up in some way, as they probably wouldn't just have 3 other people show up in your game randomly when connecting to the internet. I guess this could be how you'll use the usual linkup features too, just in the world after connecting like the union room rather than through a menu.
This is very minor but I noticed that the professors introduce themselves with Professor directly in their name and textbox label, which I thought was different and I checked the older game intros to see if it happened before. Another detail in these screenshots is that the diagrams in the background are lower for Turo because he is taller.
RBY/GSC: "My name is OAK! People call me the POKEMON PROF." (FRLG: "People affectionately refer to me as the POKEMON PROFESSOR".)
HGSS has him say "My name is Professor Oak" though, but LGPE reverts back to FRLG's introduction.
RSE/ORAS: "My name is BIRCH. But everyone calls me the POKEMON PROFESSOR."
DPPT/BDSP: "My name is Rowan. However, everyone just calls me the Pokemon Professor."
BW/BW2: "My name is Professor Juniper. Everyone calls me the Pokemon Professor!"
XY: "I am Augustine Sycamore, the Kalos region's very own Pokemon Professor."
SM/USUM: Kukui doesn't introduce himself in the intro, but he does in gameplay as "The name's Kukui" and even asks to be called Kukui instead of his full title.
SWSH: Rose says "My name is Rose, and it is a pleasure to be here." in the intro. Magnolia says "My name is Magnolia." when you meet her ingame, and random earlygame NPCs do call her the Pokemon Professor.
PLA: "My name is Laventon. I am something of a Pokemon Professor."
Overall, a professor introducing themselves with their name including "Professor" has happened before in Gen 5 (the one time that there are two Professor Junipers) and HGSS, which doesn't really mean anything. However, this is the first time that a professor's full title is included in the text box name label. Through Gen 7 and 8 it was always just "Kukui", "Magnolia", "Rowan", and "Laventon". Based on the school theory, maybe they're more of teaching professors or something more story involved.