You're not saying anything I haven't said myself hundreds of times over the years here. Names are easily changed. But names can also be evocative and help define the image of a monster in a reader's mind. My example, the witchknife, uses actual words that conjure an image, a very definite one, that jibes not at all with the actual monster. Sure, i could rename the critter and use the name for something else. But designers could also try to name critters in such a way that the names themselves evoke something in those who hear the name.