Because dragon
I thought you were on my side this time!
Didn't you disagree with the design as well, for the same reasons, even?
The Ursa is an expensive, very modern heavy bomber. Making the Ursa look like a ramshackle mess of boxes produced in the designer's shed does not send the right message. It makes it look cheap and generally pretty ****ty. By FS1 standards, that's the exact opposite of what it is.
Believe it or not, some people think "advanced super-heavy bomber" is a more defining feature of the Ursa than "designed at the end of the Great War according to this blurb that isn't even in either of its tech descriptions".
How many times I have to remind you of this? There's nothing "ramshackle" about being boxy. It is rugged, quick to make and packs a lot of armor, at the expense of maneuverability. It has also been designed and produced in a desperate situation. It is not fast, it is not maneuverable, nor does it have any fancy super high-tech stuff. This thing made tradeoffs to get its firepower. The "super-heavy" part needs to be emphasized here, not the "advanced" part. From the gameplay standpoint, it is the heaviest thing you can fly, and it is as far from a sleek interceptor as possible. It should look like it. That you can't imagine an angular design looking like anything but ramshackle doesn't mean it's impossible to make it something else. Ursa is though, heavy, utilitarian, rugged, slow and inagile. The design should reflect those qualities. That means the "rock tumbler" approach does not work well here (and certainly not something that reduces internal volume of the torpedo pods, the very thing the design should maximize).
I know I opposed bringing in Vasudans into the discussion, but now I remember they do actually have one craft that could be compared here: Oddgrim's Amun. It is the Vasudan Ursa equivalent and shares many of its characteristics. IMO, that one is done perfectly. It still looks like a box, but it's a pretty box.
It keeps the original outline in its entirety, with only slight smoothing out to get rid of perfect sharp angles. That's not to say it doesn't have curves, but they follow the lines of the original model and make it look distinctively Vasudan (quite important with that particular model, and even then, it still looks a lot like a Terran ship when untextured).