I've completed Blue Lions and I don't have a blind hate for Edelgard. I remember declaring that both Rhea and Edelgard are crazy to my husband after meeting them though. I avoided a lot of story details before release so I was genuinely surprised at the 180 her character did for me. I did not expect her to be cast as a villain, kinda figured she would be a Corrin who could do no wrong.
With that being said, I loved hating her during the Blue Lions route. I felt outside of her route the game still gave her depth as a bad guy which is good considering how one dimensional Hubert and the TWSITD are. I am bewildered that there are people who think she's a good romance. While Edelgard may not have wielded the dagger she was still responsible for Jeralt's death and the death of a lot of innocent civilians. She even states as much and now that I'm playing the Black Eagles route she hints at these transgressions during the school phase. If it weren't for my desire to see what is basically the "Villain" route I would never pick her or the church's side.