Captain America

I actually think Channing Tatum would have been a decent choice. He's not the best actor but he can pull off steel jawed patriot pretty well. Add a little more energy to his GI Joe role and you basically have Captain America.
Tatum looks the part, sure, but Hugo Weaving (who is reportedly in negotiations to play Red Skull) and Robert Downey Jr. would absolutely blow him off the screen. He's the epitome of the kind of easy, surface level casting that's held back comic book movies for so long. You can almost always fake the look, but you can't fake the feel of the character.


So I guess they're not going to do a movie with both Captain America and the Fantastic Four as participants?

The Fantastic Four movies were done by Fox, who still has the rights. Cap/Avengers are being done in house by Marvel. The only way they could use both in the same film is if Fox lets the F4 film rights revert back to Marvel. In that case, regardless of this casting, you'd certainly get a reboot of the F4 movies that is more in line with the comics, so you'd be recasting Human Torch anyway.