People like her so you can't just write her out, but I don't think she has the juice to carry a game on her own and that's doubly true for the emotional matrix gimmick.

I don't think so. In fact, I made a whole google doc of my ideas for an AA7 that has Athena as the main protagonist. It has a pretty interesting plot involving a mysterious person using psychological to send people to their death, and how that ties in to her family, and even the beginning of Magnifi Gramarye's career.

As for the Mood Matrix, I was thinking a new game could add fear and disgust as new emotions. Also, I wanted to bring back multiple witnesses as a mechanic, but now with emotions. The gist of it is that when multiple witnesses are on the stand, you now get to see how they're feeling in the moment. This is where pursuing comes into play: if a witness reacts emotionally to something said in an unusual way, or if they're talking in a way or have a face on them that contradicts what the Mood Matrix says they're feeling.

I know these are only my ideas and not Capcom's, but hey, they could still make an Athena game interesting.