With the caveat that Marvel has movies planned out until at least 2019, and that they're pretty rapidly getting to the point where you could run a cable network that showed nothing but MCU properties...there are actually some characters I still think they haven't gotten past fan rumors. I've got a few favorites I'd like to see, like:
5. She-Hulk. I'd do this as a TV series like "Daredevil" or "Jessica Jones", only a bit more light-hearted. Jennifer Walters is a high-profile attorney (I'd probably make her a district attorney) whose life turns upside-down when she's injured by mob bosses and given a blood transfusion by her cousin, Bruce Banner. (Obviously, this is something you'd have to work in later, once Bruce's whereabouts became known. I'd toss out the "rare blood type" thing, and make it an emergency transfusion given on the spot using improvised equipment.) Now she's invulnerable, super-strong, and really not interested in being anything other than an excellent district attorney because she believes in the criminal justice system as a way of dealing with law-breakers. But of course, it's never that easy.
4. Quasar. What I've always liked about Quasar is the idea that what made him a hero was that he wasn't aggressive or bitter or generally angsty. Literally, that's what made him a hero--he got these super-powerful quantum bands that could do all sorts of amazing stuff, and he was the first guy that didn't think of them as a weapon. The people who did all wound up blowing themselves to kingdom come with them. I would run with that, and make it clear that he's a hero who thinks first of his powers in terms of protecting people and limiting the abilities of bad guys to cause trouble, and then put him into an escalating series of cosmic crises where it gets harder and harder to save everyone.
3. Monica Rambeau. I grew up with her as "Captain Marvel", so to some extent I think it's a shame they're using Carol Danvers even though she's pretty awesome herself. But I like the idea of a super-powered New Orleans harbor patrol officer who takes the same approach to big epic cosmic Avengers-themed bad guys that she does to her everyday police work, and who survives the craziness by bringing everything back to police procedural principles. Every crime has a perp, a motive, a method, and evidence. Oh, and she is so not impressed by Tony Stark.
2. The Runaways. I actually think the Runaways would work better as a series of movies than as a comic, because their one big flaw as a superhero team is that they don't really have any big reason to keep fighting evil after they take down the Pride. (Yes, I know, Vaughn tried to sell the whole "they feel responsible for the uptick in crime after the Pride are defeated" thing, but it never felt comfortable.) In the movies, having a smaller number of good arcs isn't such a bad thing. And frankly, you almost don't need to touch the first story at all to make a great film.
1. Ms Marvel. Honestly, who else was it ever going to be? I really think the only reason she doesn't have her own movie yet is because they're using "Agents of SHIELD", 'Inhumans' and 'Captain Marvel' to lay the groundwork for her admittedly complex origin. (Okay, I tell a lie, it's not that complex--she got gassed with alien mist that awakened alien DNA. But comics fans will tell you it's complex.) Seriously, they don't need to change a thing, just bring her into the movies with a good actress playing her and do all the stuff they're doing right now and it will be awesome.