What are some missed opportunities?

As much as I love Hollyleaf and her own self-destruction, it makes more sense for her to be a villain, the way how she was turning out. I don't mind what we got from her, but it would have been a very interesting yet tragic for the readers if Hollyleaf ended up dying from her own self-destructive cause from the tunnels and never returned to the Clans. I don't mind what we got, but she could've been written so much better.

Dovewing. Again, I'm also okay with what we got, but rereading OotS, she was actually a very good character from the start, with a fleshed-out personality that matched well with the series. But it was wasted on romance, and I feel like the writers made her stupid just to make the story work for the other characters. It's lazy writing, and it's very unfortunate that she's a victim of bad writing. Dovewing was doing really well, with her own story almost ending in Dovewing's Silence, but that ended up backfiring because the Erins wanted to make DovexTiger look good. Even though they've become a guilty pleasure, I can't deny the awful writing quality that happened between these two characters, and they both treated each other like garbage, something that the real Tigerheart and Dovewing would've never done. The real Dovewing would've never left the clans because of a stupid dream (which was an extremely weak plot on its own) and the real Tigerheart would've picked his clan over Dovewing because he has always done that his entire life. The original ending for these two made much more sense, but nah we needed a excuse for Shadowsight to exist to make his parents look good together lol. I still like Dovewing, but I don't feel as strongly for her after the Erins continue to screw her up for the sake of the plot. It genuinely pisses me off, especially when she talked crap about her own freaking Clanmates she grew up with.

Funny how I'm critizing two of my most favorite characters, but I know their flaws of writing, and Hollyleaf and Dovewing both could've been much better characters if the Erins tried harder with them and stopped making characters look stupid just to prove the others right. It is frustrating. I really don't think they tried at all with Dovewing, who had so much potential to be an interesting character on her own. I have always liked Dovewing for her character, not her crappy romance. So I'm sad that was all wasted.

silentbreeze

i second this notion. sol should be back after swearing revenge in his last appearance.

Hazeltail, Rosepetal, Foxleap, Toadstep, and Icecloud becoming actually interesting background characters. I'll be forever salty about how they were killed off like that.

Hollyleaf's return should've been made as a villain, or at least her finishing her story. Properly, without Daddy lying for her after he acted like his sons weren't sons.
Sol. What happened to him after he swore revenge? Did he get hit by a car right after he left?
Dovewing, please. Honestly, she was such a cute, friendly somebody in the first book. Then she was made dumb and daft for Tigerheart. Her friendliness is shown in Bramblestar's Storm, because I really liked her helping the kittypets.
Background characters like Hazeltail, Icecloud, Foxleap, Toadstep, and Rosepetal.

Snowkit becoming a deaf warrior.