What exactly will be Sam's motivation?

Sam Winchester has always tended to be driven. As a teen, he channeled this energy and ability to focus into healthy paths such as a full ride to college. Once the "normal" world crumbled, Sam resorted to a more negative drive: namely, revenge. Over the seasons I've noted his motivations:

Season One: Revenge, finding Dad represented a "normal", Sam reasoned that to find Dad = finding what killed Jessica, and thus getting his revenge for his ruined life.

Season Two: Early on, Sam was grieving the loss of his father and worrying about Dean's mental health. As the season progressed, Sam's focus turned to saving as many would be monsters as possible, thereby saving himself from his demonic destiny.

Season Three was all about saving Dean from his deal, and at any cost

Season Four brought a return to revenge.. This time the drive to kill Lillith was really an excuse to drown in the power his blood gave him. There was still the occasional desire to save the monster as an analogy to saving himself, but by the end of the season, Sam's motivation may have been declared as "stop the apocalypse", but really it was show who is boss.

Season Five Sam has hit bottom and is out searching for redemption. He is still motivated to stop the apocalypse, but this time by using approved methods. In the end Sam's ability to vessel Lucifer allows him to release his ego and complete the ultimate sacrifice.

Yes, in the end, it was still, all about Sam!

Season Six! So what's left? Sam no longer has to prove he is not evil, he has demon blood and he has made a fair amount of peace with this. He has shown time and time again that he saves people and puts others' safety first. He has shown drive and dedication to hunting. He has shown he can beat his addiction. He has sacrificed selflessly by vesseling Lucifer.

I think this is where Sam will be like Season one Dean. Dean's mission: kill as many evil sons-a-bitches as possible. I think that will be Sam's purpose now, and I especially see this happening with his joining of the Campbell family.

Will Sam be radically different? No, maybe an exaggeration of his colder traits, but he's always tended towards pragmatism.