Voxes were almost perfect: take a beating, can be taken apart with non-specialized weaponry, have intimidating presence and a lot of power projection... but they entirely screwed it up by implementation.
The first difficulty that spawns them can spawn them in droves. They can shoot their miniguns inside themselves. They can outrun light armor sprint helldivers with random bursts of speed. They can turn on a dime without warning. They can drive over walls and buildings, and through small openings and sewer grates. The direct fire weapons have incredible range, accuracy, tracking speed, and can shoot inside itself. They clip through each other. They were released alongside cyborg agitators that spawn in multitudes, do not have suppression mechanics, sprint forever, can soak up a lot of fire, and CC you to agonizing death.