Harrison Ford has already been (re)cast as General Ross? I can't remember if that's a rumour, an official casting, or something in between from reputable sources.
I really like the idea of Julia Louis Dreyfuss leading a team like the Thunderbolts. She plays such a great douchebag. And the Thunderbolts are traditionally kind-of douches. I'm not sure what to make of the MCU Thunderbolts though, John Walker and La Contessa Valentina Allegra de la Fontaine being the only true douches so far. We shall see.