This is a fighter. That's the easy part. The hard part is the game itself. Even on easy mode it's hard to go all the way
1: Take it to the Cube
This is the most awesome upgrading the game from the GBA to the GCN will make a vast graphical improvement.
2: When on the Cube give it SSBM controls and an SSBM setting
This'd be really nice as a SSBM style game. As for our final boss I'll explain his new style in the 4th thing.
3: Include more characters
This one's simple from all 4 seasons there are 25 heroes each with there own digimon and that digimon's multiple forms. Pick a digimon, pick their form and you're ready to go. With each digimon having somewhere around 4 forms that makes for about 100 fighters plus any unlockable fighters that are thrown in.
4: Make the final boss your chosen character vs. his or her season's main bad guy.
This is where it gets interesting the game changes to SC2 controls and an SC2 setting for your final battle as to the battle here's an example if you're Veemon or any of his other forms you're final battle will be against MaloMyotismon while if you're Agumon or any of his forms you'll go up against Apocalymon. That'd be nice.
5: Improve the ancient cutscenes.
First off this feature would be available for all digimon except for those at the mega level. The gauge would now be under your character's name which'd be on the top right or left of the screen. Once the gauge was full your digimon would digivolve to his Mega or Ancient or whichever one is his or her most powerful. The game would then go into bullet time and show your monster pulling off his awesome attack and several different camera angles would then show the opponent getting blasted before they flew backwards into the wall or side of the screen. Still no falling off.