It's a problem I've had with Skyrim since the drop. They want to make each side equal in a grey vs gray conflict, but really that just means making them each suck equally. Asking who's my favorite, the colonizers or the xenophobes, isn't exactly winning me over to any side. They can all dunk their heads, I'm just here to fight dragons.
It's why New Vegas is my preferred faction-based open world game. Choosing NCR vs Independent NV is a much more interesting choice than Empire vs Stormcloaks (Legion is just there for pure evil characters).
I think this is really selling the work Obsidian did on the Legion short. What I love about New Vegas is that even the evil faction isn't just "evil for evilness' sake", like so many other evil RPG factions are. Caesar's Legion definitely is evil, there's no doubt about that, but Caesar has created the Legion using an example that he feels would be "best" to recreate society, namely snippets he read about the Roman Empire and philosophical ideas about society's functions. Like, he didn't wake up one day and went "Fuck it, I'm evil now".
In that way, the Legion does serve as a sort of dark counterinage of the NCR. The NCR thinks they are much better than the Legion, but in fact they are not that different. They just take a different old civilization as their inspiration and are usually a little less ruthless in their tactics (as in, no slavery or crucifixion and women have at least some rights and can hold leadership positions). Throughout the game though, there are instances where the NCR is far more ruthless than the Legion though.
For example, if you play the NCR side, you can never peacefully deal with the Khans. The NCR wants them all dead and there's no way you can budge the NCR to not kill all of them. Even if you manage to convince the Khans to flee, the ending slide mentions that the NCR slaughters them all on a later date. The Legion is far less intense with the way they handle other tribes, as they take the Roman approach, where tribes are allowed to live semi-independentally as long as they provide troops. Now, no question that that approach also isn't ideal and the game does mention that tribes that do not agree with the terms of Caesar are exterminated, but it shows that the Legion is far more developed as a faction than just being the "this is only for pure evil players who just want to see the world burn".
I mean, I haven't even gone into how between the NCR and the Legion, the Legion is probably more accepting of LGBTQ relationships. In the NCR is flat-out stated that being gay isn't, uhm, encouraged. Meanwhile, the Legion's relationship to LGBTQ people is more complicated, with the higher ups in the Legion claiming it is illegal, while actual LGBTQ characters in the game mention that same-sex relationships in the Legion are common and not as stigmatized as in the NCR.
