Why The Black Widow and Hawkeye Should Get Their Own Film(s)

Here's an idea I had the other day on the next Marvel movie, since we've had films about each Avenger depicted in the movie except two.  Spoilers for The Avengers are coming...

In The Avengers, when Black Widow goes to talk to Loki, she describes her history with Hawkeye and how he "made a different call" when he was sent to kill her.  Although she makes a Suspiciously Specific Denial about them being in love, she does describe how she "owes him a debt" and wants to clear the red off her ledger.

A prequel film depicting the Black Widow as a villain and Hawkeye being sent to kill her before changing his mind for whatever reason would be really interesting.  I'm not familiar with Scarlett Johansson's career, but I don't think she's ever played a full-blown villain.  And the amount of character growth/development on her end could be a good exercise for her acting ability.

Hawkeye makes an appearance in Thor and the Black Widow in Iron Man 2, but unlike the rest of the team, they haven't gotten their own films.  The situation I'm describing could even be done in two films.  The first movie could be called Hawkeye and feature him being sent after her and end with him bringing her back to SHIELD rather than killing her.  The second film could be called The Black Widow and feature the fallout from Hawkeye's reinterpreting his orders.  Perhaps as "the price of redemption," SHIELD requires her to kill a former employer or mentor?

(She makes a reference to killing for anyone for money.  Given the comic character's Soviet back-story, she could be an unemployed KGB agent who became a contract killer the way many ex-Soviet military-intelligence types got involved in the Mafiya.)

In the second film, she could undergo an "evil detox" and realize just how bad she'd been before.  This could be the beginning of her "quest for redemption."  This article here makes a good case too.

Y'all like?  I personally would love to see this.  Hollywood types, take note.