perhaps adding wheels to the feet for faster mobility and shock absorbtion [tires] similar to the Fuchikomas and Tachikomas from GitS. Or maybe tank treads...used for fast approach and spreading the weight out, but can convert to "walking mode" if treads are damaged, or terrain dictates, as well as to "unmask" from behind cover to fire and then "remask" to move while using the terrain to your advantage. Just a thought.
Althou I am not a fan of multi-legged design, maybe because I'm arachnophobic, but I can see your point. -Two-legged designs are highly unstable, one shot from a weapon with sufficient impact recoil and its down to the ground. -Hovercrafts would be fast and nimble but their consumption of Anti-Gravitron particles would be unsustainable and I haven't even talk about CG barriers and weapons. -Tracked vehicles would lack the extrem cross-country mobility that leg designs offer and wheeled vehicles would be just too vulnerable to be used in head-on battles. I think that pretty much sums it up.