If you reread Bob Harras' Avengers run, you'll notice two things...
1. It wasn't all that powerful of an Avengers team
2. Black Widow really doesn't DO much
That's why, I'd have Captain Marvel II take over as Avengers chairperson during Widow's tenure.
I do not think it would change any of Harras' stories, really, and all it would do would be give Captain Marvel II some much-needed exposure.