*Tournament mode with forced ratio system
I'd just like to say that I'm totally opposed to this idea. It's one thing for players to implement a ratio system to encourage variety, while it's another thing entirely for the
developers to assign values to their characters. If they think the game is imbalanced enough to require that, why don't they just re-balance it?
Developers adding a forced ratio system just smacks of laziness to me.
5. Fully fleshed out storyline
*Though it's a fighting game, there are people who actually do play it for the storyline, and Blazblue mopped up with this. King of Fighters has a rich history and lots of storyline to it. Besides the team story that goes in arcade mode, some more detailing could go in story mode and even have a single character mode to show their individual stories.
I'd argue that individual stories don't fit in KOF, because the story is about a team-based fighting tournament. For me, team stories are what make KOF what it is.
As an alternative, I'd suggest a simple profile mode where you can see each character's sprite, alternates, and read up on each character's backstory. Also, perhaps they could add a tracker for keeping track of what intros and win-quotes you've seen for each character.
Arcade mode has challenges built in to each fight. For example, when the round starts, there is text at the top that says something like combo 2 lights. These get harder as the match progresses. In order to get the best ending, the player has to complete the challenges.
In order to get the good ending, you just need to clear stage 6 with over 2.5 million points. The challenges don't have any direct influence over that. All the challenges do is give you more bar and drive meter, which is quite nice, as it allows you to do more combos. (Actually, the challenges can also add 10K to your score, but it still only indirectly affects the ending.)
Also, there isn't a great deal of variety in the challenges (there are eight total), and it isn't character-specific. I'd say there's certainly room for a 98UM/2002UM/XI/MI2 style challenge mode. In fact, I'm hoping for one.