If there's one existing comic book movie character who hasn't had their own movie yet, but who definitely deserves one, it has to be Black Widow. Scarlett Johansson has portrayed the character brilliantly since 2010's Iron Man 2 and has subsequently appeared in four more movies in the Marvel Cinematic Universe. Natasha Romanoff has such an interesting history, but it's only briefly been touched upon in the movies. A solo movie would give audiences the opportunity to see more of it, while getting more kick-ass Black Widow action - something nobody would complain about (especially not the guys).
As far as comic book characters go, there's really nobody more interesting than the Joker. He's undoubtedly the most popular villain in comic book history and he always garners a lot of interest when he's portrayed in a movie - so why not give him one of his own? The likes of Jack Nicholson and Heath Ledger have already played the character, and Jared Leto is set to do so in Suicide Squad, but a movie that focuses solely on him as the lead character could potentially be exceptional. A detailed look into his twisted mind and what drives him to torment Batman would really immerse fans. And seeing him put his intricate but totally crazy plots together is always a real treat. If Leto proves popular as the Clown Prince of Gotham, DC and Warner Brothers should definitely consider making him the lead in a future movie.
Namor the Sub-Mariner
Namor the Sub-Mariner is a classic Marvel character who has been around for as long as the company itself. If anyone deserves a movie of his own, it's Namor - and it's unforgivable that he hasn't been given one yet. Of course, he was hinted at back in Iron Man 2, when a S.H.I.E.L.D. map appeared to show his home kingdom of Atlantis, but the Easter egg hasn't been followed up. However, now that his DC counterpart Aquaman is getting his own movie, Marvel Studios should undoubtedly follow suit. He's interesting because he's incredibly powerful and his moral alignment is unclear. A movie with him as the star would undoubtedly be unique and well worth a watch.
2016's Deadpool movie was absolutely fantastic - and the closest thing DC could do to replicate the tone is produce a movie based on Lobo. The space mercenary and bounty hunter is also known as The Ultimate Bastich, The Main Man and The 'Bo Master Frag - all because of his bad-ass attitude and huge personality. A Lobo solo outing would be gory, funny and irreverant - just like Deadpool - and he would be an awesome addition to DC's live action line-up. The best thing about this is that it's rumoured to be in the pipeline. Can you imagine The Scourge o' the Cosmos going toe-to-toe with Henry Cavill's Superman or Gal Gadot's Wonder Woman? It would be incredible!
Why should superheroes get all the glory? This year's Suicide Squad will see a supervillain team headlining a comic book movie for the first time ever, but supervillain solo movies don't really happen - and that's a crying shame. Early reactions from screenings of the Suicide Squad movie suggest that Margot Robbie's Harley Quinn is the standout star. If that's really the case, she should definitely be given a movie of her own. She's a quirky, fun, sexy and interesting character with a fantastic ongoing comic, so there's definitely an audience for her, and Margot Robbie's star has never shone brighter. A movie that looks into her origins - in which she was driven insane by the Joker, but also became his lover and accomplice - would be awesome.