Led by a less extreme, more rational Caesar, the New Legion has united scores of tribes, bringing them forcibly to the light of civilization. Settling his subjects in what fertile lands remain in Arizona, New Mexico, and Colorado, as well as bringing what settled peoples remain under his protection, whether they like it or not, The New Legion is a more stable state than its canon incarnation, with its power coming not from wholesale enslavement and plunder, but from
Latifundia and
Coloni, large estates and tenant farmers with
slightly more rights than slaves. Not merely that, but veteran soldiers of the New Legion are given their own small plots of land that they can call their own, tend to, and as they are still heavily armed, even defend.
But what happens when there's no more fertile land to give away? Well, that's why the New Legion still needs to expand west.
Ceasar still feels contempt for the NCR and Mr. House, and desires to bring his version of civilization to the Mojave. Although more willing to negotiate and compromise on the outside, that is all to hide his and his new army's determination to take what they they desire. Due to being based on land instead of slavery in this universe, though, they are much less numerous than they were in canon...but also better-equipped, organized, and led.
Even the minor soldiers wear armor and riot shields that can deflect small arms, while guns such as revolvers and cowboy repeaters a more common sight. The mid-tier soldiers have what the elites in canon have; brush guns, super-sledges, and ballistic fists, while as for the true elites, the true elites are clad in true bulletproof armor made from Pre-War meta-materials and reflective, anti-laser plating, and carry miniguns, plasma casters, and longer swords that emulate the late roman 'spatha' instead of the 'gladius'.
As for their treatment of women, the New Legion does
not treat women like cattle; they are allowed to defend themselves and to do paid work, but one sexist law still remains: Women
still cannot join the Legion.
And now, for the final difference from the original universe:
Slavery. The New Legion does not actively enslave people. Slavery is still legal, and the Legion turns a blind eye to it, but slavery is a soldier's private business, and no effort is made to impede or support it. Basically,
this Caesar turns a blind eye to slavery instead of endorsing it, although he is glad for the taxes it gives him...