Maybe it was inevitable with a cast of characters so big, but I'm still bummed about how some main characters got next to no development or screentime, namely the angel loli sisters, who ended up never being more than half comic relief, half props for Eden's own character growth, and then they become completely sidelined once their adult counterparts join. The trailer for part 3 made it sound like we would witness firsthand their growth and how those two came to be feared by so many monsters.
Then there's Erubetie, who already got the least amount of attention in VN, still feeling like a complete blank page while all the other Heavenly Knights get actual character arcs. And to make matters worse, she's literally a clone of Kanade who has the exact same issue, but with the 6 Ancestors.