I really disagree. The aliens being insects is perfect because it provides a justaposition with the human characters. The idea is that the insects are a swarm of mindless drones. Meanwhile, the humans are…well, also a swarm of mindless drones. Which is sort of the point of the movie. The fascist society they inhabit actively dehumanizes them and robs them of their ability to think for themselves. The visuals of the film reinforce this in the larger fight scenes: the mass of gray bodies that constitute the human forces all blend together into a single swarm, much like that of the insects. And by the end of the movie Rico is completely hollowed out as a character: literally just inhabiting the same role as Rasczak, and even parroting all of his phrases from earlier in the film.