Now that Wilson is Captain America, ...CA 4 can do the Serpent Society, Madbomb, Madam Hydra and Red Skull in a hottub, turning Presidents into lizards, etc.

I like to add some 'Falcon' themes to CA4 (If Marvel Studios make that movie);

NIGHTSHADE. She first showed up turning Falcon into a Werewolf, and brainwashed a bunch of SHIELD agents. And she did all that in a bikini, thigh-high boots and twin Afros (Then she wore a lab suit and turned Steve Rogers into CapWolf, not fun).

Stoneface. A forgotten New York gangsta', probably because he's been ex-patrioted and sent to Africa where he kidnapped Leah and tried to throw Falcon and the Black Panther off a cliff.

Leah, Ralf, and people living in Harlem. Well, the people living in Harlem rallied together to fight the Commie-smashing Captain America to rescue Falcon. Ralf hates Sam, Sam likes Leah, Leah likes Ralf, Leah hates Captain America but likes Falcon. Lots of tensions.

Hey, I wanted to mention Nightshade. I thought there was a lot of story and fun that can come from this character (I liked that line she said, "Oh Pooh!")

What about Machinesmith? He's a traditional Cap villain, and his control over machinery would make him a nice foil for FalCap, who relies heavily on his mechanical wings and mechanical (in MCU) Redwing.

Throw Zemo in to keep the waters good and muddy and you've got yourself a movie!

Stoneface can become Machinesmith, ...one of MS robots merge with SF.

I just wanted something 'Sam Wilson, Falcon', not just an African-American Captain America. No one read Falcon's first limited series??? No one but me liked what future Black Panther writer Chris Priest did to Falcon in that 2000 series Captain America and the Falcon???

Attacked by a malfunctioning Sentinel robot, mucking around a Super-Sailor, ...were all attempts of developing the Falcon universe (Like Spiderman having all those Animal supervillains, like Doc Oct, Lizard, Rhino, etc). Didn't succeed, but people tried.

Plus, Nightshade first attacked Falcon (Turned him into a Werewolf), so, I'm guessing she's Falcon baddie. Hey, I'm not the only one who would love to see a Hot-looking woman in a bikini being BAD and bringing Chaos and Mayhem.

Captain America 3 was suggested to be a 'Madbomb' version, where Cap fought zombie-like American civilians, ...hey Nightshade could've came up with the formula to turn civilians into Zombies. Or develop a cure, or manipulated by the elitists behind the Madbomb, I think it was someone named Turro.