In the grand tradition of mixing genres in with a superhero movie, how about a space noir?
Hal is paired with Thaal Sinestro on an interplanetary investigation that involves whole settlements being wiped out. Think a buddy cop movie with a space opera's settings for the first half, with interrogations featuring good cop/bad cop, debates over lethal force and it's place in an interplanetary police force, and maybe some foreboding warnings from Atrocitus.
While traveling, our Green Lantern displays a hot-headed and even vindictive attitude towards some traditional space powers, like the slave taking Dominators and the xenophobic Daxamites. We also learn about Abin Sur and his sister's affair with Sinestro in contrast to Carol and Hal's issues.
Our heroes are similar to Brad Pitt and Morgan Freeman's detectives from Se7en, but with both being recruited by different Guardians (Appa and Ganthet) to investigate each other (Jordan for being insubordinate and downright defiant to the Guardians' commands, Sinestro for the suspiciously peaceful nature of his home planet).
The Villain? Initially a small but powerful cadre of reactivated Manhunters driven by faulty programming. Jordan's maverick style tactics lead to trading information to Atrocitus in exchange for tales from the past (the Guardian's failure with the Manhunters, and a brief flash of the Blackest Night). The fight ends up leading to Korugar, where we discover that not only has Sinestro enforced a regime based on fear, but that the citizenry was responsible for signaling the Manhunter's reactivation in hopes of killing him.
Sinestro and Hal face off, with a lot of personal anger between the two. Hal wins by thinking tactically about how to scare Sinestro, weakening his ring, and outlasting the older officer's power charge. Sinestro is imprisoned by the Guardians but it's revealed that Atrocitus used Hal's information to escape and somehow destroy nearby colonists who were supported by the Guardians in the desolate Sector 666.
Hal submits for punishment as well, but Ganthet successfully argues for a simple restriction to Earth affairs for a while, as well as a new two members per sector policy, leading to the selection of Jon Stewart.
Our end credits scene reveals the other power spectrums being revealed as Atrocitus' earlier prophecy echoes through Sinestro's mind.