Oh, I don't know--I suppose I see what you are saying about the disconnect in how much one improved compared against another in that entry, but not everything can be improved at the same rate in every title, and at the end of the day the weapon does look perfectly average to me, considering the hardware. But I'm just going to seize the opportunity to point out how phenomenal that game looks in general--that entry is truly a (if not the) highwater mark for visual design in the franchise. For all the complaints (many reasonable, many often exaggerated or just fanciful) drawbacks to that entry in certain mechanical details, it can't be denied that it is just gorgeous:
It best establishes the balance between the more animated and photorealistic approaches in models and textures; has a gorgeous application of colour with super-saturated highlights but brilliant gradient maps that keep those colours from making the image look flat and fake; some great character design (your mileage may vary on this ever contentious aspect, I know); and, perhaps the crown jewel, probably the best stage design of any Soulcaibur game--though it does get stiff competition from its immediate predecessor, SCIII--with brilliant staging for both aesthetic and mechanical purposes, lively interactive elements, background activity that is employed in a way that adds a sense of depth and being rooted in an actual environment without looking terribly fake as sometimes happened with SCV, and well considered details, all delivered in a crisp image with appropriate focal lengths.
It's just a beautiful game with visuals that never wore out their welcome and set a standard that I just don't think has since been matched by either SCV/SC:LS's Street Fighter- and anime-inspired designs or an approach in SCVI that I think can only be realistically called faithful but rather bland, overall.
Which, SCIV or SCVI?