These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Akira is definite female example in the series. Her popularity relative to her role in United By Fate is rather large. Seijyun seems to be created just to give her her own story separate from the Gedo guys' adventures.
In United By Fate, Hyo and Sakura were also considered top tier characters. Gan also had an infinite combo.
In Project Justice, Roy, Hideo and Momo all were considered top tier.
Needs More Love: The series hasn't seen a new installment since Project Justice thanks to its poor sales. The real kicker is that PJ left the series story on a cliffhanger (Kyosuke has gone missing and Kurow has escaped), so unless the series finally gets a concluding installment, the fans may never know what happened.
The Woobie: Yurika. The poor girl is only is participating in Kurow's plans because of how much she cares for her little brother (and this is in spite of the verbal abuse he heaps on her). If the player manages to get an ending with her in Project Justice's board game, she also reveals she doesn't like the things she's had to do as a part of the Darkside Society and pleads to the player character to forget about her so the PC doesn't have to face the wrath of the society with her.