>>724762712
More realistically, she could make a good "main girl" too.
Kyoko and Chiaki were too competent and supportive, Kyoko literally solved cases for you and Chiaki was always supporting Hajime and guiding everyone through the trial.
Mahiru as a cooperative but assertive "sidekick" who's willing to challenge you and push her own theories could be a nice change of pace. Going from butting heads more early in the game to being more fully cooperative and trusting your judgement by the end would be a good character arc and pair really well with her tsundere relationship tease. (You kind of get this with Maki in V3, but not really since she's extremely confrontational (tsun-tsun), focused on Kaito and doesn't really give Shuichi her unconditional support until Chapter 6).