I think WSS's depth is mainly in the women. Anita and Maria have notably more depth than Tony and Bernardo, if you ask me (or if you look at the writing). And especially with the film version of "America", Bernardo and the Sharks have more nuance and insight for the audience into their side of things/perspective than we get from the Jets except perhaps in "Krupke".
I agree that it seems odd, especially with Spielberg taking the directing helm, that he didn't bring in a latinx female (though specifically a Puerto Rican and/or latinx immigrant... not all latinx experience is the same) -- though as a screenwriter, a lover of musicals and a writer of the book/lyrics of a musical masterpiece, I think Kushner is one of the most qualified people you could want aside from his race.
But I don't think the women are the ones who need *more* depth, over the men.