As I finished watching the second season of Daredevil which was great, and what I want in the third season which includes the Bullseye, the full return of the Kingpin, and more Punisher, but as I thought I realized who I truly wanted to see was Scarlett Johansson and Natasha Romanoff even if I doubt it will ever happen as Marvel Entertainment seems to go out of their way to keep the films and TV shows separate outside of references to each other, and some very minor guest appearances.
This seems to be an unpopular opinion when it comes to hard core Marvel Comic fans and certain shipper communities, but I am a huge fan of the Bruce Banner and Natasha Romanoff friendship/relationship. There is a lot of misinformed hate for the relationship, Johansson, Mark Ruffalo, and Joss Whedon that none of them deserve.
I loved basically everything about Bruce/Natasha. While some may deny it you can even see some brief chemistry between the characters and actors way back in the first Avengers film. In Age of Ultron the relationship was handled great outside of the farmhouse scene that Whedon could have handled a little better, and Johansson and Ruffalo had wonderful natural chemistry on screen. It's rare for Marvel Entertainment to take any chances with their films always playing it safe, but the Bruce/Natasha relationship worked wonderfully and I am happy to hear that Marvel is most likely going to continue it in some capacity.
Now with that being said if there is one selfish element I want in the Marvel Cinematic Universe and that is the Matt Murdock/Natasha Romanoff relationship. I am a huge fan of both characters in the comics. Even though they have their differences over the years Matt and Natasha understand each other and love each other even if their not together, and then there is Brian Michael Bendis, David Mack, Bill Sienkilwicz, and Klaus Jasnon's masterpiece End of Days which says all there is to say about Mathew Murdock, Daredevil and his relationship and love of Natasha Romanoff.
End of Days Below
If you haven't read Daredevil: End of Days I highly recommend it as I it is my favorite Daredevil story line and one of my all time favorite comic tradebacks. I don't know if Charlie Cox and Johansson would work well together or have chemistry on screen, but I would love for Romanoff make an appearance in Hell's Kitchen and for the Black Widow and Daredevil to meet.