form follows function and that set is tall and standing. all the action is at the hip joint this limits the speed. but would make it a highly stable platform. to be honest at this point it's to early for legged gun platforms, Wheeled and Tracked platforms are still the better option particularly if you get larger guns.
True legged platforms on the battle field are better for support of infantry by being able to keep up with them. anything bigger then a horse and it starts loosing function. once you hit that scale It's more efficient to transfer over to wheels or tracks. it also makes more sense to move there for armed platforms as they would be more stable and can offer larger capacity and gun option. A platform say the size of your average Toyota on 4-6 wheels with a gun system packing a heavy caliber machine gun like a 12.7mm or a 14.5mm and a number of ATGMs powered by a commercially available V8 would be faster and more stable. If that lacks the Terrain you like then base it on a Commercial mini Dozier.
I am thinking this is not for flat land but mountainous areas like Tibet and valleys. It may be hard to spot this gun hiding among large rocks. Also the fact that it can carry and use heavy weaponry in areas where fire support vehicles otherwise can't enter could give an decisive edge.
Or maybe use it as a movable, flexible sentry gun for mobile outposts in above environments.
even then it's iffy sure you would have a good ground clearance but where is the power supply? no power source no movement no movement no use. at the top speeds of this thing with thin spindle legs moving at the hip we are looking at something that although it might be a okay rock crawler would have no real mobility