I get the impression that Perlmutter and his 'Marvel Creative Committee' were in large part responsible for the culture that drove away some actors and filmmakers back around then. At this point the Committee is long since out the picture, with Feige and co. now having full control of Marvel Studios, so I can see that people like Portman might be willing to look at coming back.
There's a history lesson I may need here
the jist of it is that perlmutter was really sexist. and maybe racist? its been awhile since i read about it so i could be wrong about the last part. the sexist part is definitely true though
i remember when eric masterson became thor for a bit in the comics, and this could be like that with her discovering what all she can do. trouble is, itd be a lot like shazam