There is plenty of debate about how Disney (DIS -1.01%)/Marvel's Universe should proceed into its third cinematic "phase," which kicks off with the release of Ant-Man in July 2015.

There are plenty of rumors about solo films for the Hulk and Black Widow, but many fans are also fascinated by the prospect of a Black Panther film as well. Black Panther was introduced in 1966 by Stan Lee and Jack Kirby as the first black superhero in American comics. He is the alter ego of T'Challa, a tribal chief in the fictional African nation of Wakanda. His powers, granted to him from a Panther deity, include superhuman strength, elevated senses, and a resistance to magic.

Black Panther. Source: Marvel.

Marvel Studios President Kevin Feige has repeatedly hinted at the development of a Black Panther film, but the project has been stuck in development hell since the 1990s. Three years ago, Marvel hired Mark Bailey, a lesser-known screenwriter, to pen the script for the film, but nothing has been confirmed since then.

Although a Black Panther film is still up in the air, let's take a look at three key reasons that Marvel should take this project a lot more seriously.

1. Easy integration into the Marvel Cinematic Universe
The story for a Black Panther film practically writes itself. In the comics, he plays a part in the Age of Ultron storyline that will serve as the basis for Avengers: Age of Ultron, the final film of Phase 2, in May 2015.

Vibranium, a precious metal only found in T'Challa's home nation of Wakanda, has already appeared prominently as the material used to construct Iron Man's armor and Captain America's shield. Black Panther also builds his armor and gadgets from vibranium. More importantly, Black Panther is one of the earliest members of the Avengers in the comics.

Therefore, it's much easier to connect Black Panther to the rich tapestry of Disney's Marvel films than other recently reclaimed characters like Blade, Punisher, Ghost Rider, and Daredevil.

2. A pulpier universe needs edgier heroes
As we move into the second half of Phase 2, the future of the Marvel Cinematic Universe admittedly looks much weirder than before.

Guardians of the Galaxy, which will hit theaters on Aug. 1, will be a major test for Marvel. To non-comic book fans, Guardians looks like a strange John Carter-like space opera starring a Han Solo look-alike, a green assassin, a raccoon with a blaster, and a walking tree. Even Disney doesn't seem convinced of the film's profitability -- it recently debuted 17 minutes of the film to audiences across America for free to test the waters first.

Guardians of the Galaxy. Source: Marvel.

But even if Guardians is a hit, Marvel still has to worry about Ant-Man, another tough sell that is now being directed by Yes Man director Peyton Reed.

In my opinion, Marvel needs a darker hero to offset the pulpier characters in Phase 3. Marvel's films are well-balanced in terms of seriousness and darkness when compared to Time Warner's (TWX) deathly serious Dark Knight films and Man of Steel. Yet it couldn't hurt to finally add the darker heroes of Marvel's roster -- like Black Panther, Blade, Punisher, Ghost Rider, and Daredevil -- to the Marvel Cinematic Universe to balance out the lighter qualities of Guardians and Ant-Man.

If Marvel can market Black Panther as "Marvel's Batman," as fans frequently call him, it could add a much-needed serious edge to Marvel's films. Time Warner certainly knows how profitable Batman can be when he isn't pulling out his Batman credit card -- Christopher Nolan's Dark Knight trilogy grossed a whopping $2.46 billion worldwide on a budget of $585 million.

3. Diversifying the Marvel Universe
I'm not a fan of forcing diversity for the sake of diversity, as seen in some films with token roles for minorities, but Disney's Marvel Cinematic Universe should try harder to mirror the diversity in ethnicities, cultures, and sexual orientations that its comic book universe has boldly embraced. The new Ms. Marvel, for example, is a teenage Muslim girl. The new Spider-Man, in the Ultimate Universe, is a black Hispanic teen. Mutant speedster Northstar is openly gay.

The new Ms. Marvel. Source: Marvel.

In Disney's Marvel universe, the only prominent roles played by minorities are Nick Fury, James Rhodes/War Machine, Sam Wilson/Falcon, and Heimdall. To Marvel's credit, Samuel L. Jackson's Nick Fury is based on the Ultimate Universe version for Fury (the original Nick Fury was white), and it cast Idris Elba, a black actor, to portray Heimdall (who is also white in the comics). But those are baby steps compared to sweeping changes that Marvel has made in its comic book world.

That's where Black Panther comes in. As an African tribal chief who becomes "Marvel's Batman," T'Challa goes far beyond being a token minority character in the Marvel Universe. It also fills a void in black superheroes that hasn't been filled since Spawn and Blade. More importantly, it would be a poetic response to racist criticisms about Heimdall's casting in the Thor films.

The Foolish takeaway
In conclusion, Disney and Marvel have done exceedingly well so far with their patient, brick-by-brick construction of the Marvel Cinematic Universe. But as the universe gets bigger and bigger, so does its importance as a key growth engine for Disney's Studio Entertainment segment, which accounted for 13% of the media giant's revenue and 6% of its operating income last year.

With Iron Man, Thor, and Captain America all gradually showing their age on the big screen, Marvel needs to keep its universe fresh with new heroes. Guardians of the Galaxy, Ant-Man, and Dr. Strange all represent fresh new opportunities for growth, but Marvel would be doing its fans a great disservice if it doesn't make a Black Panther film as well.