They can distinguish character traits while still keeping two “shy-ish” characters. For example, one could be a fraidy cat type and the other could be the quiet bookish type. And again, they’ve already got like four other spunky characters with overlapping character traits.
I’m just making the point: there were other ways they could’ve done things. Making Bumblebee a somewhat quieter girl than she usually is didn’t necessarily mean they were forced to cut Jessica’s anxiety. That was a choice they made, and personally I think it was a bad one.