And that's fine o:
Like, that's perfectly fine, that's valid.
I'm not saying she's a bad character. She's not a weak character. She had more than just Auracite, she had more than just a short-lived presence. She was more, otherwise people would DEFINITELY have forgotten her. If that were the case, that moment on Aitiascope? No one would bat an eye, and I've seen people actually remember Moenbryda faster than they recognized Haurchefant's help xD
But, for example, if you're a fan of Moenbryda, did you enjoy the times Mikoto went on about her? Because that for sure flew under many people's radar even at the time. Mostly because Bozja/Ivalice was considered boring, some because Mikoto is about as good a character as drywall. And what I take from that isn't "Moen sucks so hard that they gave her character development to an underappreciated character lol". It's "The devs still clearly care about developping Moenbryda, even if it's a little bit. It's just unfortunate it had to be through someone like Mikoto.".
Now, the impact she had on you specifically? That I can't speak for. All I can say is that it's valid, alright? But when it comes to the plot itself? Her being so short-lived didn't have as much of an impact on the majority of players as it should have for someone presented with such relevance and spotlight. So while it's totally fine for you to feel attached to this character, the issue is that for myself and for many people, she wasn't handled well. At all. And that interfered a lot with how people received her past her death. Which definitely killed a lot of the momentum she should have had.
So the issue there comes from how the parents scene speaking more volumes about Urianger, the one we can connect to the most and we know more about, than Moenbryda whom we didn't have the proper chance to connect to as well as other Scions.
Keep in mind, this is all purely subjective. Just because myself and other people feel this way about Moenbryda, it DOES NOT mean you're in the wrong for liking her and having a larger attachment. Okay? o: AT ALL.
Again. It's fine to disagree. But I'd argue it's even more fine (is that a word?) to like and appreciate Moenbryda, even if the rest doesnt' as much.