If only I could downvote your post...... would make me feel better Already had my ticket for sunday and everything.
Spoiler: Psychologically speaking... Natasha aka Black Widow doesn't really have a strong audience following and influence among the Earth superheroes community as compared to Tony Stark, Iron Man. You need the final viking funeral sendoff to be Tony Stark, Iron Man to make the total full impact. And finally to close the loop of an Era in MCU.