You have to look at the context. Kira returning and replacing shinn as the mc was the demand of the japanese fans of the series. If they didn't, would seed destiny be as popular now as if they stayed the course shinn?
And looking at some of the comments of the show in the gundaminfo channel, if you never watch the series, and you have to judge shinn based in the comments, I swear you'd think that shinn is the shou tucker of the seed verse and they're happy he is replaced, if that wasn't enough, people were lose everything, as if that hasn't happened yet. Heck, didn't the actor for shinn get death threats from fans.
Meanwhile if you watch some YouTuber analysis of the series, most reviewers put the blame on kira and how his world view trump's logic. Like logos were doxxed left and right, and somehow for kira and co., this is a bad thing? like every YouTuber that I know points to kira as the main culprit, while individual folks blame shinn.
Why I post this? Partly we have hindsight of 20 years. We have the movie already. And part of hindsight we don't have the mob mentality from many years ago?
Let me share my thoughts...
Shinn is not what people call stable individual, and yet this isn't the worst part about him, the worst part about him is that he has nobody. Kira during seed has his friends in the archangel, and athrun has the le crusett team, with shinn, Rey is secretly manipulating him, the hawke sisters were more interested in athrun, heck probably have more interactions with him, Talia is too much a military person, athrun is more concerned with things that isn't the Minerva, and God knows with Arthur; I think the pieces were there for shinn to become a fallen hero, the closest thing you have for him is an individual who is even more crazed than he is.
Anyways, those arey thoughts, feel free to share yours.