Anyway, here's my fanwank take...
First off television seems like the better avenue to me. This seems like the Marvel property that's tailor-made for the format, with the buddy-cop detective story making it feel naturally episodic but the supervillain aspect giving it larger, seasonal arcs. Plus its stars are popular characters with powers that can easily fit into a television budget.
Also, it seems like the perfect opportunity to flesh out the MCU without having to resort to crappy tie-in books or comics. So being set in the MCU seems like a must to me. However setting it in New York seems like it might bring about continuity issues, so I think setting it in another large, thus-far untapped city seems reasonable. Someplace like Seattle or Chicago.
Here's one potential break-down of characters
Main Cast:
Luke Cage aka Power Man: Lance Gross
Betrayed by his childhood friend, he breaks out of jail after being experimented on and flees to (whereever), where he meets and joins forces with Iron Fist to form Heroes for Hire.
Danny Rand aka Iron Fist: Scott Porter
The son of a deceased wealthy businessman, and wielder of The Iron Fist.
Jessica Jones: Jessica Stroup
Cage's on-again off-again love interest. Pilot is focused on Jones coming to Heroes for Hire for their services.
Davos aka Steel Serpent: Sung Kang
Iron Fist's hated rival, exiled from K'un-L'un. Cross's right-hand man.
William Cross aka Crossfire: Bruce Greenwood
Disgraced ex-CIA agent turned seemingly philanthropic CEO of Cross Technological Enterprises (CTE) when his ailing cousin steps down. Sort of like the Kingpin- funds all sorts or illicit activity and runs the city's criminal underground.
Recurring Cast:
Marc Spector: Jensen Ackles
Cross's former partner at the CIA, whose research into Cross's current activities has him occasionally at odds and occasionally aligned with Cage and Rand. Could potentially become Moon Knight and spin-off into something separate further into the show's run.
Bobbi Morse aka Mockingbird: Taylor Schilling
Spector's current partner, undercover as an employee at CTE. Could potentially become a SHIELD agent further into the show's run.
Maya Lopez aka Echo: Jordana Brewster
One of Cross's mercs, raised as his own daughter. All of the comic backstory would obviously replace Kingpin with Cross.
Willis Stryker: Omari Hardwick
Cage's childhood friend whose past betrayal and framing comes to a head during one of the show's arcs.
Misty Knight: Annie Ilonzeh
Colleen Wing: Maggie Q
Heroes for Hire's rivals in the detective biz at Knightwing Restorations, Ltd. Could potentially team up with and eventually merge businesses with Cage and Rand down the road, becoming part of the main cast.