My desires also exceed what is realistic to be expected. I'd really want to see new battle mechanics and get away from the old slot-based turn-based system, at least for group battles. I'd love to see a system akin to what Dragon Ball Fusions does, which is still turn-based, but you get more turns if you're faster and it has actual positioning. The current system feels more like a trading card game than an actual battle, and I think in this day and age the main pokémon series should at least try to make the battles a bit more dynamic like in the anime, we're not in the 90s anymore. I know it's probably not going to happen, fundamental change like that'd undoubtedly receive a lot of hate, and it'd require a complete rebalancing of the battle system, but I still wish it would.
Walking pokémon behind you I'm a bit mixed on. It's cute but hard to do right, there's always that strange thing when you're walking around with Arceus following you and nobody you interact with even cares, and having something like Seaking following you around is also just strange.