>>149753317
>Black Canary
Too weak compared to the rest of the cast (yes I realize Batman is right there but at least Batman has a tech empire to back them up / detective skills, Dinah would just be the weakest fighter with a sonic shout that never works) and you just can't include Black Canary without also bringing in Green Arrow and the main cast was big enough as is. I know you can also make the argument you couldn't have Shayera without Katar but the difference is that GA/BC are different enough in their aesthetics and powersets it'd be a crime to have one but not the other, whereas Hawkman/Hawkgirl are identical in all but gender
>Zatanna
Too strong compared to the rest of the cast, can't think of many situations where her reality altering magic wouldn't just solve everything by speaking backwards. Also very visually similar to Diana (black-haired babes in leotards) so she wouldn't stand out visually.
Hawkgirl was about the only other reasonable choice they had if they really wanted another girl on the team - she's stronger than normal and can fly but isn't THAT strong and Hawks have a legacy with the League