No, just that she has been queer coded since the very beginning (again, "Suffering Sappho!". It's not subtle) in addition to being a gay icon. So Rucka writing her as bi is just confirming what was already an open, poorly kept "secret".
Where does the desire for her to be straight come from? Her being bi doesn't eliminate the romance with Steve. Wanting her to be straight seems to come from the desire to fulfill a quota.