A bit part of why Moengryda's death fell flat for me was the scene right after it.
Moenbryda does her big sacrifice, making it clear she had some sort of revelation right before she died.
Then Uriangr comes in, lamenting about how her death is partiuclarly tragic because she never figured out the thing. But fear not, for we heard her say that she finally understood right before she died! How nice! Maybe it would have been nice to develop her in this way BEFORE she died and then not have the awkward post mortem exposition?
IF you're going to count Yotsuyu, a villain, you should count Livia as one too for ARR.