I could see it for a couple of the green and even sinestro.
Hal - The most obvious choice and the one most likely to be John's hero of the hour. Has fought hard for redemption so that he could be forgiven for betraying the corp. I think we may end up seeing him become the Ion of the spectrum. The one to find the balance. (Sadly this will go the way of the red/blue superman, but it is suggested in Legion (cant remember which boot) where there is a girl who controls all the emotional spectrum))
John - after his failure on Mosaic and death of his wife, John has often times felt guilty and like he has to prove something (see his arrogance). He was the first human "guardian of the galaxy" a dark star and then a lantern again, It could be he finally finds the inner peace to allow him to forgive himself.
Sinestro - Sinestro is a good villain because he, like lex luthor, aren't doing evil for evil's sake. Sinestro truly wanted peace and order on his home planet, that drove him to use his ring for negative reasons. Even as a Yellow Lantern he used his ring to conquer so that he could bring order. I think him picking up a green ring again would allow him to finally remember what being a Lantern is all about.
Mogo - Mogo has been threatened to be killed by Ranx in Blackest Night, while Sodom destroyed the physical body of Ranx, I think something remains and it will infect mogo, turn him into a sort of war world where Mogo accepts Ranx so that they can end the conflict in the end, but destroy both groups.
Guy - Guy is my pick because if you read Corpse they have slowly built him up as the greatest Lantern. He is Alpha of the honor guard, he is rash but people listen, he has really fallen into his own. I think we may see him lead the last charge of the light brigade ending and get a heroes send off. (I.E. Ted Kord) keep in mind he was one of the league of victims that DC seems to enjoy killing lately.