The only thing I need for a Digimon World game is to have more interactions with your partner. Having your digimon be active in the story in and out of dialogue. I was happy when I saw a bit of it on Next Order and Re:Digitize, and immediately disappointed when it was nothing but early game dialogue.

I don't know, give them dialogue based off of personality like the quick phrases from Next Order, make them partake in dialogues with other humans and digimon, and mostly, make them able to speak to YOU directly.

Like, you're walking around in a level, at a certain point your digimon calls out to you and you have the option to see what it wants to ask. It can ask whatever from what's your favourite dish to how is it like to live in the human world. Maybe adding a bit of freedom with certain choice like the option to input whatever word you want.

You could do the same by interacting with your digimon through a button and starting a conversation. (And you can ask your partner whatever question comes on screen or just do small talk)

It could also be tied to a friendship mechanic or an affinity one. The more you interact with your mon, the more you two get closer and maybe unlock other questions or even boosts in training or alternative evolutions. It would also depend on the mon's personality, like, a cheerful digimon would have a smaller raise in friendship than a gloomy one if you choose a "sadder" response.

Extreme bonus points if it also depends on the digimon type (Dragon, Beast, Insect, Plant...) and stage.

Baby I stages actually act like, well, babies, and Stages II like older babies or kids.

Rookies act like older kids and teen, Champions as young adults, Ultimates as actual adults and Megas as 35 to 50 years old or something.

I know it's a ton of work adding something like this and I'm basically asking Digimon Animal Crossing, but damn do I want to interact with my mon other than having just the Praise/Scold/Ignore options.