My suggestions

It would be nice to have eggs and pre update (a long time ago) digimon back.
Allow us to get some cool digimon like beelzemon, imperialdramon PM, and Crimson gallantmon. Dont make them overpowered but just the same as a regular DNA.

Also more mini games or quests would be cool. Such as having to learn abilities like swimming or trivia games for bits.

I would love to see an update to the item shop with like swords, shields or whatever you want for stat boosters and 2x exp tickets.

Forgot to mention throughout the game unlockable digivice upgrades like you start out with the scanner and stuff but you can unlock more things on it like the exact stats and a list of digimon beaten with like locations or something. I would also like to be able to freely switch to any digimon after mega without having to degenerate back to level one.

I would really like there to be a place where you can store your items and D-souls. This would be more convenient because of how many items we really do get. Especially now with the In-Trainings. I mean, you randomly get a whole whack of them out of nowhere. And most of them are pretty good digimon, so trashing them would just be even more annoying. Maybe make it an option in the bank on Browser Continent?

I think we could use some sort of bulletin board. Something people can just write a message or note on, for people to read. For example, if someone needs a certain digimon, or needs a digimon trained and is willing to pay, they could post a note on the board, for players to read.