I have never played anything else that hits the nail on the head of just how much potential games have for storytelling than this one.
Although it has been talked to death, if I could offer one unique takeaway from it, then it would be this...
The Legion playthrough could have a few more unique quests, but I still believe it is the best way to play the game as you are met with the most consequences for your actions, both internal to the game's progression and externally as your own morals are persistently questioned. To me, it is akin to the genocide route in Undertale, you may be able to beat it as a videogame, but there is never a sense of victory for anyone in the Mojave, not even Caesar. The Legion offer a unique observation on the history of slavery and oppression, similar to Django Unchained, but fairly detached in what they represent. They ARE powerful, as is the cruel and unjust nature of man that has always and will always be a revoltingly pervasive side effect of our existence on this earth.

Loses some points for not letting me shoot children like Deus Ex though :(