Except theres no reason to add musculature and fat too cartoon characters!
You're completely ignoring the point being made. I said it was just an example. I don't think the next Smash will go that far, but let's say they want better expressions. Better cloth physics. Or just better detailed models with a higher polygon count, more vertices, better texture work etc.
For a different example, look at Mario's model in Odyssey compared to his model in Smash. Odyssey's model is more detailed and expressive. If they have better tech to have better models with more expressive animations, do you not think the devs would try to do so? You know, gradual improvement as we've seen throughout the series (or any series) history.
And this is just character models, what if they want a more detailed Skyloft that isn't just an asset rip? More dynamic lighting, or other environment changes.
Or moving away from improvements, what about just gameplay changes? What if they want to add a entirely new mechanic or other cast wide feature? Now you have to rebalance everyone around that change in addition to any individual character changes that were already being done?
And going back to address the muscle/fat thing, I don't think they would ever go as detailed as SF6 for every character but to say that it can't apply to cartoon characters is silly. And there's the fact that you have plenty of less cartoony characters on the roster anyway.
Take
, resident fat, muscle man. If they wanted to give him some of his Wario Land flexing as taunts, he could benefit from this. Again, make it more exaggerated or less detailed, but it would serve to make Wario more expressive.
Or what about a character like Ike, maybe Palutena? Muscle tension when RD Ike is charging Smash attacks or subtle breast/thigh jiggle on Palutena. It's not limited to that either. Better cloth physics for capes and dresses. Going back to Palutena, they could add more movement/sway to her necklace/jewelry as she moves, etc.
And before you say that Smash doesn't need any of these things, try to think about what a developer might want to do. Granted I'll make it clear again that I don't expect Smash to try all of these things or implement them to the same degree. However, as devs/artists there is a desire (and need for the sake of selling a product) to make improvements like more detailed models or better expressions or insert whatever. (For a recent example look at Super Mario Wonder)
It's a quality vs quantity thing too. We as fans might see the roadblock of all the work keeping the roster large creates. We can say, "just reuse all the assets" to justify more quantity, but quality matters too.
