Keith's shoddy artwork aside, you can make an argument that an egg layer - the Egg Layer of Egg Layers no less - shouldn't need arms. But then she wouldn't need legs either really. She has an entire planetful of Aliens at her beck and call.
Unfortunately that makes for a stupid looking design.
I think Cameron got it pretty well right. She was big and obviously powerful, but wasn't really made to fight. Anderson made her more of a dinosaur.