Ed Harris as Logan
For this role, you'd need an actor who's capable of showing a lot of inner rage and restraint; someone haunted by their past. I think Ed would be a great choice, as he's an actor who has a rough exterior and can not only play a badass, especially if you've seen A History of Violence; but he can also bring a strong emotional core to the film. Also, Ed is that right age where he's not too young for the role, but not too old either. May need to bulk up a bit. Maybe have him workout with Hugh Jackman for a couple of weeks :P
Clancy Brown as Clint Barton/Hawkeye
A relatively unknown and underappreciated actor. Clancy is around the same look and age for an older version of Hawkeye. He's also pretty familiar with comic book movies voicing characters from Odin to Parallax. I think they could really finally utilize him in a live action comic book movie finally.
Alternatively, I'd also cast Jude Ciccolella (but to be honest, Clancy seems like a more fun choice wouldn't you say?)
Maria Bello as Maureen
Maria looks the part; she's also a strong and capable actress who could equally handle the gravity of the situation that her family is in.
Jared Gilman as Scott Logan
Kara Haywwod as Jade Logan
Both of these kids were great in Moonrise Kingdom. They're around the same age as Logans kids; and they have a great chemistry on screen.
Peter Fonda as Abraham Donovan
Fonda has the look of Abraham, plus I could see him and Ed Harris having a lot of chemistry on screen.
YaYa DaCosta as Ashley Barton/ Spider-B*&!#
I've always thought YaYa was an under-appreciated actress. She'd be a good choice for Spider-B*$!^ and a lot better then some of these people suggesting Rhianna for the role (WHY!?)
Idris Elba as The Kingpin
I can see the comments now, "I'm tired of Idris being cast for a lot of these roles". I'm not :) In fact, he's a versatile actor and I think he enjoys making movies just as much as we do watching them.
Thomas Jane as The Punisher
Ben Affleck as Daredevil
Both actors would be a great call-out to their past performances with those characters. Good or bad, their performances are always never short of an opinion. Still, it'd be great to see them both one more time as the characters.
January Jones as Emma Frost
I didn't particularly like January as Emma Frost, but perhaps she could bring a different weight to the character in this film. I'm not going to give up on her just yet.
Richard Jenkins as Black Bolt
Has the look, and he's always been more of a comedic actor this could be a nice change for him.
Zack Gallifinakis as Tobias
Tobias is a fake, pretending to be the leader of the resistance. I know Galifinakis is a comedic actor; but this could be a nice change of pace. Where maybe he starts out charming and very 'Galifinakis' but then as the deal goes sour he becomes this hardened person, no bullshit. Could be a memorable role for the actor.
Hugo Weaving as Red Skull
Might as well try to keep continuity if the performance was good and the actor can get away with playing him still.
The Hulk Gang (CGI)
Voices:
John Dimaggio as Otis Banner
Steve Blum as Charlie Banner
Kathy Najimy as Bobby-Jo Banner
John Malcovich as Bruce Banner
He looks the part, plus in terms of playing a crazy old man -- John is pretty much typecast for the part.
Some Other Articles of Mine:
FAN CAST: Fantastic Four
FAN CAST: MCU Daredevil
10 Ideas for an ABC Marvel TV Show
Guardians of the Galaxy (plot)
Guardians of the Galaxy (cast)
What I'd Like to See: The Avengers 2
What I'd Like to See: X-Men First Class 2
Fan Fic: Star Trek 2