Its the posture and size of the armor.

On the left, it looks imposing due the straight posture, smaller shoulders and streamlined chest.

On the right, it looks dump because of the arched back posture and bigger chest and shoulders, that coupled with that stupid helmet and the color and shininess of the materials, makes it look like she is wearing a bloated plastic suit.

Left: Scruffed up and dirty armor in places implying she was in plenty of sick battles and lived to tell the tale, bag that shows she's prepped for absolutely anything out there, signature look of superiority, strong posture showing intimidation and authority, helmet looks sturdy and congruent with the rest of the design, gun that while I can't see the whole thing looks like a single blast could gib someone as hard as Doomguy's super shotgun despite looking somewhat cobbled together from bits and bobs
Right: Armor that simultaneously looks poofy and not sturdy and also looks like she's getting ready to play American football as opposed to provide protection against bullets, no bag, helmet that looks like it was bought at Party City, blank stare like she has sub room temp IQ, generic minigun she borrowed from The Heavy, posture in practically every single image I see is one lacking initiative