I wondered if it had been tossed aside along with her accent when that didn't play well in test audiences.

That's interesting -- I hadn't heard about the accent. But I think it might be possible, because what she did was so invasive, perhaps it was considered incompatible with someone working with the "good guys".

MCU romances, especially those that only exist in team-up movies, tend to go from 0 to 60 as a consequence of all the time that passes between films, so having some time to explore their relationship properly would be nice.

Indeed.