Quoted By:
Battle Frontier-like hubworld.
Lots of various battle types like from Frontier.
Rental Pokemon.
Your own mons from HOME.
Custom trainers with custom poses, custom battle music from various games, custom backgrounds.
Multis.
2-4 player minigames from Stadium.
Move tutors from all old games.
The ability to pause in the middle of a match and leave it seamlessly incase you need to go ASAP but dont want to be penalized.
C&D Showdown for the ultimate seethe.