I have the same opinion as Opellulo and romanoi who commented long before me: the main character... How should I put it? I'm sorry to say this and really hope it won't hurt anyone's feelings...
The MC looks flat. The colors on them, especially skintone and hair color, looks like it's painted with a single color (plus another color for the shadowed area) on a separate picture, then cut out and pasted on top of a far more detailed art. It's so out of place when standing next to other characters with realistic-looking skintone and highlighted hair. It's jarring and sad.
I enjoyed Arcade Spirits and didn't mind the MC much back then, because they rarely appears on screen. Maybe it's just because Magical Diary made me got used to MC sprite that looks like they belong with the main cast. Anyway, I'm sure it must be hard and costly to design a customizable sprite. My only hope is that maybe there can be an option to turn off the MC sprite so that they doesn't always appear on screen.