Maybe Kycilia told you that the Zeong is only eighty percent complete, says the mechanic, but it’s at one hundred percent of its operational capability. Legs? Legs are merely a matter of appearance, whatever the officers think.
I find it impossible not to see these remarks as reflections on Mobile Suit Gundam‘s shortening and on the constraints that merchandising places on mechanical design. Coincidental reflections, perhaps, but amusing ones.
At the same time, I’m grateful for those constraints: one Zeong is nice, but a show full of Zeongs would lack that something that humanoid mecha bring. And in some ways the Zeong is just as ludic-rous, with mega particle cannons for fingers, on hands which it can launch in a freakish rocket-punch-gone-wrong attack. Those Zeon engineers certainly love their white elephants.
Animanachronism 
I never thought of this! Quite a delicious insight.
Also, re a show full of Zeongs: the humanoid form is, I argue, the most accessible and most beautiful for (myself, obviously) and viewers. We enjoy seeing bodies move through space (not necessarily outer space), but we prefer human bodies vs. multi-tentacled blobs and what not. As such I do maintain that humanoid mecha shows (and therefore, Gundam) carry the possibility of entertainment via animation.
You don’t really need legs in space (which was the battlefield the Zeong was engineered for), but Char needs his robot to have legs in order to perform his trademark kick! A lot of 4koma have been made to make fun of this.
Or maybe it’s one more way of illustrating how pressed for resources Zeon was by the end of the war, thanks to their fixation with the Big Zam.
I guess the ultimate OYW dream fight would be the Alex against the completed (Perfect) Zeong.
I’m watching Victory Gundam with a couple friends right now (about 10 episodes in), and despite all the fighting so far being in-atmosphere, it’s already become a joke that Gundams in this show don’t need legs. In fact, it would probably be a better financial decision to not make the things, since they just get blown up instantly and don’t seem to add much combat capability when you can just fly around the whole time.
Alternatively, launching a fully-formed Gundam instead of sending it out in pieces in the middle of a battle might be a good idea; one that I think has only been used once in those 10 episodes.
In a world where giant motorcycle land battleships are simply the logical next step in military technology, launching the Gundam in pieces is comparatively sane!
I think Uso mostly uses the legs as something he can detach and launch at the enemy, but I do remember him decapitating an enemy MS with a kick at one point.