For a development team to create something that has a different body structure, it requires many things - planning, r&d, modeling, rigging, weighting, animating, pathing, and AI. A different body shape requires it to move differently, react differently with its environment, and also possibly requires a brand new set of movements - what we call an animation tree.
Which is why I'm saying that it would be nice if the developers of a new SF game would make the effort to build multiple basic body structures into their game from the ground up, accounting for such variety in their initial planning and budgeting, so that we could see some genuinely imaginative aliens rather than just humanoids all the time.
Games like these are stuck in boringzone. Always the same 4-5 character archetypes (healer, warrior, blabla), and always the same humanoid avatars.
I think developers wouldn't take the "risk" of changing those things.