While this is mostly accurate, Sugu's boobs being so big are, in fact, an actual certified fact because it's the only you can look up the ORIGIN of! Why? Because originally, in the first version of SAO (The Web Novel), they weren't, back then Kawahara, the author, didn't care about breast-size at all, just writing the story, so in his mind all the girls were mostly flat if they weren't adults, in fact here is a very old pic of 'Proto-Sugu/Leafa' that was drawn by the author himself, not the illustrator of the novels, of how he originally envisioned her:
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However, ironically, as a fact that can actually be checked with sources if you look it online, even in her Wikia page with citations to the official sites where this was stated, his editor when he was adapting the series to Light Novel suggested amongst its many changes to make Sugu's boobs big (Why? Because...just because, lol). It's in the 'Trivia' section of her Wikia page if anyone cares to check:
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So yeah, while it's true that different artists/creators will indeed draw characters differently, Suguha actually dwarfing all the other girls' in tit-size is consistent across all SAO media because it's literally an established fact that it was a change suggested and made when the series became a LN XD Hell, this is an illustration made by the novels' artist during the time the latest anime season was airing, which shows that, yeah, even he draws them that big:
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Sugu's breasts seem 'smaller' in earlier-novel-illustrations not because they grew but because the illustrator literally had like a whole decade to make his art better at depicting things, like, have you seen Kirito and Asuna in the cover for the first volume compared to the latest one? The difference is like night and day, hard to even tell they're the same characters outside the designs:
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As an extra, and if anyone cares, while I agree that all breast-sizes are great, here is a much more blatant 'size comparison' from the manga-original Spin-off "SAO Girls Ops" (Featuring Sugu, Silica, Liz, and the original new girl Lux/Hiyori, as their main characters) with an 'aerial view' of the 4 main girls in a hot springs:
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