I agree with Voltage on this. It gives you developers the flexibility to design newer parts later, to broaden our gameplay better than us crafting entire kitguns repeatedly. Take Zaws for example. Of all the strikes, I only used Mewan, Balla and the Plague Zaws. I don't bother to explore the other Zaws as I don't want to disappoint myself by rebuilding a whole new modular to improvise it, or scraping something that I already stacked with forma. Kind of removes the 'fun' aspect of modular weapons, but I can only use so much weapons.