I initially would’ve suggested camo troopers, but like others have said, the all-white Imperial troops are reflective of Palpatine’s arrogance. Really, many aspects of the Empire are reflective of his arrogance and scare tactics. The AT-ATs are clearly less effective modes of transportation than the tanks in ROTS, but they’re also clearly more visually impressive and intimidating. The Death Star could’ve been stripped down to the size of a capital ship, consisting only of the superlaser, a control room, and engines to get 'er moving, but he chose to make it moon-sized with living quarters and hangars instead 'cause seeing an artifical planet-killing moon in the sky would make the population of a world crap their collective pants.

If Palpatine wasn’t utilitarian when it came to walkers and battle stations, why would he be towards grunt armour?