8) Increase The Training-Based Mini Games
Super Training was an interesting inclusion in Pokémon X & Y because it brought the training techniques used by competitive battlers to a more widespread audience. The whole thing became far more accessible, and players really had to think about what they wanted from their top battlers.
The only problem with the training exercises was a distinct lack of variety. While the benefits made the mode essential, the monotony that soon set in turned the experience into somewhat of a grind before too long. If the developers could add a greater variety to the types of exercises each stat can be trained by, it would stop the boredom from setting in quite as quickly.
Another potential addition could be environment-based training opportunities, where different skills can be trained at lakes, forests or caves. At least there then would be a greater aesthetic variety to each exercise!