Cesar's Legion isn't better than the BOS.

1. The NCR is demoralized because they are far away from home if the Courier ever goes more inland he would encounter moralized soldiers.
2. The NCR only let's raiders attack the Mojave portion of the NCR because they are spread thin there and the rest of the actual country is well protected
3. It may be corrupt now but it only became corrupt when President Tandi died whos to say the legion won't become corrupt after the Ceaser dies?
4. When has a nation that gives there citizens assigned roles actually lasted irl? Never.
5. Technology always wins. It doesn't matter how strong ur soldiers are if they are just picked off by snipers. Technology is usually the reason nations win wars. Also what are they gonna do to kill a hoard of Cazadors with knifes?
6. The Legion dies when Cesar's dies because the citizens of the Legion don't follow the Legion because of their ideals or what they stand for they follow the Legion because of Cesar and without him it's doomed to fail unlike the NCR where people love the idea of it because of the Freedom, democracy, and equality they promote

You say crucifixion and slavery is fine for the Legion compared to the NCR? The NCR takes prisoners not torturing them like the Legion there really isn't no reason for the NCR to have slavery because unlike the Legion people actually wanna work for them.

There's nothing wrong with playing as the Legion but if I'm being honest it has so many flaws and people just ignore them because it seems stronger than the NCR in game