Timothy Olyphant as Bullseye
A seasoned actor is what this role needs. Someone who can demand the screen while looking as silly as possible. If Chris Evans can do it then so can Olyphant. Olpyhant in my mind could definitely portray the villain and sometime Avenger Bullseye.
Alice Eve as Carol Danvers/Ms. Marvel
An under appreciated actress who's acting abilities gets jilted due to her looks (see Star Trek: Into Darkness).I find her acting very credible and she has the ability to portray someone who can without a doubt give the toughest hero a run for their money. Alice is my choice because she can deliver her lines in a way that you won't be focused on her beauty the whole time and actually accept her as the popular superhero.
Benedict Cumberbatch as Stephen Strange
It may seem like it sometimes but Dr. Strange has not been cast yet. There are many fan favorites for the role after the rumors and top preferences were dropped and Cumberbatch is simply my favorite among the rumors.
Dianna Agron as Valkyrie
Valkyrie is a super heroine that if put in the MCU could give Lady Sif a run for her money. An Asgardian by birth, Valkyrie, also known by her real name Brunnhilde, was selected by Odin to lead the Valkyrior. Agron seems to be a young up-and-comer that is surely headed for stardom in the future.
Marion Cotillard as Jennifer Walters
Marion is considered by some to be one of the greatest actresses of all time and I feel she could bring Jennifer Walters to life the same way Ruffalo brought Banner to life. You should be interested in the character before they turn into giant green savages. I feel Cotillard could bring that to the role better than the normal picks like Ronda Rousey (why?) and Gina Carano considering She-Hulk should be CGI.
Garrett Hedlund as Richard Rider/Nova
Not a particularly creative fancast but one I hope gets done, Nova is pretty much set to appear anytime between GOTG and GOTG 2. Hedlund is an underrated actor that I feel should get cast in a CBM sometime soon.
Jared Padalecki (very close second)
Michael Jai White as Luke Cage
I usually see The Rock or Terry Crews for the role of Luke Cage but I'm surprised I haven't seen anyone go with MJW. Originally my pick for Black Panther, I see alot more Luke Cage in White. He's no stranger to action as he's played Mike Tyson, Jax from Mortal Kombat and he's an accomplished martial artist. While he would be good for either role I can definitely see him being the Hero for Hire.
Dave Franco as Alex Powers/Powerpax
A very promising leading man who can without a doubt contribute to the comedy of a movie, Franco is my (slightly older) choice for Powerpax. I choose Franco because I doubt Marvel will work with children unless it's from the say-so of a star like RDJ or a necessity. My bet is they cast a more mature Powerpax and I think Dave could do the job. (He's already played a high-schooler right?)
Jayma Mays as Rita DeMara/Yellowjacket
Jayma is a solid actress and considering the Ant-Man film is taking place after Hank Pym's run as Ant-Man then they should have Rita DeMara, who stole his identity at one point and is known as the villain Yellow Jacket.
Ryan Gosling as Captain Marvel
Gosling is a glossed-over actor that people don't usually consider for a CBM because he tends to do romance films, big budget movies and comedies. However ,with the rise of the CBM and the second, third and fourth highest grossing films of 2014 all being comic book films and with no signs of slowing down, I think it's only a matter of time before Gosling enters the fray and portrays a character. If so, I think he would make an excellent Captain Marvel. This was not a easy decision by any means but Gosling is an actor that I think commits to his work and would do his best to give us a faithful adaptation of the character.
Chadwick Boseman as Black Panther
I admittedly had not been impressed by Boseman as an actor and had not considered him for the role until Draft Day and then being impressed with his presence after seeing the trailer for Get on Up in theaters. This convinced me that he should be given a shot as he's got alot of publicity under him right now and could bring star power to the film.
Willow Shields as Cassie Lang/Stature
This would be a necessity. Cassie Lang is a great character and will no doubt appear in the upcoming Ant-Man film. If the character is to stay and eventually become Stature then you can't really do better than Willow Shields who is an accomplished actor and is no stranger to the business.
Olga Kurylenko as Agent Anesthesia
Olga is a good actress that can play Agent Anesthesia, the secondary villain in the film who will serve as the personal quarrel for one of our heroes considering she works for AIM to aid her father who is in a coma.
Emma Watson as Jeanne Foucault/Finesse
A polymath with the ability to instantly master any action by looking at it once. It is suspected that she might be the daughter of the Taskmaster. Emma Watson is a proven actress that, in my opinion, is looking for that next breakout role in her career. Playing and popularizing the character of Finesse will offer her up future roles and expand her filmography while also adding even more star power to Marvel.
Dustin Clare as Taskmaster
With work on shows like Spartacus he certainly has the physicality to portray this villain and his acting chops have been proven to be more than okay. Should Marvel choose not to go full-on CGI then Dustin Clare would be my pick for the man villain of a Marvel hero solo movie.