大は小を兼ねる is an idiom meaning "better too large than too small" ("you can use a big thing instead of a small one", eg a bucket instead of a glass, but not the other way around). She's turning it around ("less is more") and saying that they have many friends who prefer a small girl to a big one.
You became very... well... sexy after coming backUm.. well... do you really think that was for the best?Did you think that through?!Rosa, calm down!I'm very happy I was able to grow upRydia...Porom is supposed to be the token little girl, right?So, once you take a look at it all,Rosa, you're scaring me!Rydia, can I ask you something?What do you mean?You don't fill the role of token little girl anymore!I've never met her before, thoughdon't you think we make a balanced group?What is it, Rosa?Because the flow of time is different in the UnderworldRosa, I don't understand what you mean!I'm going to kill you with Cures, you little bitch!ARE YOU CALLING ME AN OLD WOMAN?!