[AgileSiamang7]

For me:

Have a Tamer have at most 3 Digimon partners, like in most games, and nothing more
If there's to be DNA Digivolution, and not that Xros Fusion stacking on nonsense, make the combo Digimon actually look like a combo of the two, not just a new thing that's slightly related (looking at you, Ankylomon/Angemon).
Final enemy is an evil Tamer and his partner, not just some evil Digimon or Data entity
Royal Knights, if they are there, aren't asshats and actually side with/look out for the protagonists when they're not busy
If not the Royal Knights (that would be a surprise), please use the Olympus Twelve as the go to mythological pantheon
Kumamon/Bearmon is one of the main partner Digimon. Because I freaking love DigiWorld 3.
Maybe not cards like Tamers, so as not to step on its toes, but how about have the Tamers supply elemental chips in their new digivices that add power to their partner's attacks.
A Matt stand-in that isn't as much as an ass that he was (like Koji, something I actually like about Frontier).
Maybe one person with a Digi-Beetle. Because I'm a sucker for a tank.
A Digimon with a White Mage role.