WWE has one thing in mind when it comes to their characters and storylines, and that is making money. As a result, when it comes to turning a beloved babyface heel, Vince McMahon wants to be very careful about making that call. For many, many years, fans wanted to see John Cena turn heel to freshen up his character.

It never happened, and there are two big reasons -- John Cena sells a lot of merchandise to kids, and he does a lot of Make-a-Wish Foundation events. WWE can't turn him into a bad guy and have him to heel stuff for that to work. That remains true recently for Roman Reigns, but the characters and storylines suffer for it. With only the characters in mind, here are 10 WWE superstars who could use a heel turn.

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10 10. Finn Balor

10 WWE Superstars Who Could Use A Heel Turn

Finn Balor has been a fan favorite since he arrived in WWE. He was a babyface in NXT even when he pulled out his demon persona, which made him more popular. When Balor arrived on the main roster, he was an immediate star and was the first-ever WWE Universal Champion. However, an injury ended that reign after one day.

Due possibly to the injury, Balor never reached that level again and has been stuck on the mid-card. He is still winning lots of matches, but he hasn't been a serious world title contender since. For those who don't know, Balor created The Bullet Club in Japan and has Luke Gallows and Karl Anderson in WWE with him. Re-creating the Club in WWE as a heel faction could relaunch Balor to the top.

9 9. AJ Styles

10 WWE Superstars Who Could Use A Heel Turn

If Finn Balor doesn't become a heel and restart the Club, AJ Styles should. When Balor left New Japan and headed to WWE, Styles took over as the leader of Bullet Club. When Styles joined WWE, Gallows and Anderson followed, and they both made main roster debuts along with Styles.

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While WWE teased the Club at times, it never went all in on the faction. Styles soon became a babyface and remains in that role today. While it is hard not to cheer for AJ Styles, he is a tremendous heel as well, and his recent babyface run has been kind of boring. A heel turn could reignite Styles and set him off on some great storylines.

8 8. Big E

10 WWE Superstars Who Could Use A Heel Turn

The New Day is one of the most popular factions in WWE today, and they sell a ton of merchandise. On top of that, Big E has become the loveable and goofy big man of the group. Remember, Big E is a former NXT Champion, something almost no one remembers to this day.

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While New Day will likely never break up due to their connection with the fans, if WWE ever wants to get behind Big E, he could be a fantastic villain if he betrays Kofi Kingston and Xavier Woods and sets out on his own. He will always have tag team reigns as a New Day member, but if he wants to sniff a major singles title, it needs to be on his own.

7 7. Seth Rollins

10 WWE Superstars Who Could Use A Heel Turn

Seth Rollins is a natural heel forced into a babyface role. This situation is interesting because when The Shield initially broke up, many fans felt that Dean Ambrose was the natural heel and Seth Rollins was the great exciting babyface. WWE saw it different, made Ambrose the heel and then Rollins succeeded above all expectations as the heel world champion.

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Seth Rollins as the fiery babyface Universal Champion has fans excited, as they all chant "burn it down" but Rollins is better suited as a heel, someone who only cares about himself. Yes, he is popular right now, but eventually, Rollins needs to return to the dark side where he is at his most natural in the ring and on the mic.

6 6. Bayley

10 WWE Superstars Who Could Use A Heel Turn

Bayley will never, ever turn heel. When Ricky "The Dragon" Steamboat was on top of the mid-card as a babyface in the '80s, he said he asked to turn heel because heels always have more fun. WWE rejected his request because they believed he was the perfect babyface and fans would never buy him as a heel.

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As a result, from the time that Steamboat was the babyface fighting Randy Savage at WrestleMania III to the end of his career, he was only a babyface. Bayley is that person. Little girls love her, and there is no way that WWE would turn Bayley heel and destroy a little girl's idol. However, imagine if the Hugger went dark and started to change. It could be the best heel turn ever.

5 5. The Usos

10 WWE Superstars Who Could Use A Heel Turn

Right now on Monday Night Raw, The Usos are in a feud with The Revival. Neither team is the Raw tag team champions, and the story is just The Usos humiliating The Revival week after week. The Usos come to the ring and make fifth grade jokes about The Revival and make fun of them shaving each other's backs.

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Meanwhile, Zack Ryder and Curt Hawkins are the Raw tag team champions who are doing nothing. The Usos are not a babyface team that makes fun of the heels. The Usos are a mean tag team who brutalizes their opponents while talking smack. The Usos need a heel turn more than any other tag team on the roster.

4 4. Roman Reigns

10 WWE Superstars Who Could Use A Heel Turn

Roman Reigns' leukemia battle ensures that he will not turn heel anytime soon. Before his cancer returned and he fought to beat it again, fans wanted Reigns to stop acting like a Superman-styled good guy and get mean and violent and turn heel. Like John Cena before him, Reigns talked the company line.

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Reigns said he wasn't a good guy or a bad guy -- he was just The Guy. That made fans boo him even harder no matter who he fought. Reigns would fight the meanest and dirtiest heels in WWE and fans would cheer on the bad guys because they hated babyface Roman Reigns. Right now, Roman is getting more cheers due to his cancer battle, but WWE needs to turn him heel before fans turn on him again.

3 3. Sasha Banks

10 WWE Superstars Who Could Use A Heel Turn

Sasha Banks came up from NXT and helped start the Women's Evolution with Charlotte Flair and Becky Lynch. Sasha was a tweener at that time, but with Charlotte as such a perfect heel, Banks ended up as a babyface. For the first year of the Evolution, Banks and Flair wrestled in first-time historic women's matches and traded the Raw women's title back and forth.

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Earlier this year, Sasha Banks and Bayley became the first ever WWE women's tag team champions. While Banks is missing in action right now due to her dissatisfaction with WWE, she floundered for the last year as a babyface. Look to her NXT run where Banks was a cocky and mean heel and that is her best fit. If Banks returns, she needs to come back as a heel and immediately turn on Bayley.

2 2. Aleister Black

10 WWE Superstars Who Could Use A Heel Turn

Aleister Black has always been a strange WWE superstar to classify. When he was in NXT, he was just an edgy wrestler who ended up in the role of a babyface thanks to a feud with Tommaso Ciampa and Johnny Gargano. Then, he was called up to the main roster with Ricochet.

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Black still didn't have a real persona -- just a cool entrance. He is no longer teaming with Ricochet as a babyface tag team and is on his own on SmackDown Live, but there is no telling what he is doing as he has only done vignettes asking for someone to pick a fight with him. Aleister Black needs to be the one picking fights, and he needs to do it as a heel.

1 1. John Cena

10 WWE Superstars Who Could Use A Heel Turn

Fans screamed at the top of their lungs for WWE to turn John Cena heel for years. WWE refused, knowing that Cena was a cash cow that brought in monster merchandise sales. He was also their goodwill ambassador, especially with the Make-a-Wish Foundation and different cancer charities.

However, Cena is a part-time star now who only shows up a handful of times a year when he is not making movies. Since Cena is no longer a top guy and he is not full-time, his merchandise sales have to be lower, and he is taking on more adult roles in movies, even as bad guys in some movies. Now is the perfect time to give fans at least one run with what they have been begging for as Cena could return as a heel like The Rock did when he came back from Hollywood. It is time to let John Cena finally play a heel again.

NEXT: All Of John Cena's Wrestlemania Matches, Ranked