You know, I never thought of it that way, but you might be on to something there - the reason they gave Rose Tico that frumpy wig and curve-concealing clothes was so she wouldn't upstage Rey. Because in every Mary Sue story, the lead girl has to also be the most attractive one.Oooohh, I'd put a baby in her.
...wait, that would mean they went out of their way to make her unattractive with a vengeance and on purpose?!
Why? Because they wanted people to fap to Rey and her chiclet incisors?! They frumpied up an asian cutie to prop up their staler than 3 week old white bread Mary Sue?
... that's racist.