Don't know if you've noticed, but Obsidian doesn't have a whole lot of reasons to abide by a design philosophy that matches the real world. In fact, their art department has had a history of giving that sort of thing the finger.
I mean, for god's sake, the baddest-ass of the badasses of the NCR in Fallout: New Vegas wore rodeo jeans with a longcoat, and for the Legionnaires old football shoulder pads somehow equates to kevlar body armour. And it doesn't take an engineering major to figure this out (hell, I majored in art and I figured this out), but a big robot that relies on a single wheel for locomotion is not the soundest chassis design for a weapons platform.