But this Rick disappeared once they got to Alexandria. If you watch his video interview with Deanna, everything he says about bad people outside the walls now applies to him. "They measure you by what they can take from you." He is measuring the Alexandrians, and said he will take Alexandria. He may not be the governor, but so far he is the villan of season 6.
He has nothing but contempt for the Alexandrians. They've been allowed to pretty much ride out the zombie apocalypse in relative comfort. As he told Morgan, "They haven't had to survive. They've just lived." And to paraphrase about Carter, "A guy like him shouldn't even be alive."
He certainly isn't going to let any of them call the shots.
You have to look at Rick through the lens that his only goal is keeping his family alive. And by family, we mean not just Carl and Judith but his extended "family" of everyone who has helped him or the people who he cares about survive (meaning everyone he arrived to Alexandria with except Father Gabriel).
This was the same goal the Governor had, keeping Woodbury alive. Recall the Governor didn't start out evil. Prior to the ZA, he was a regular joe, a family man who had lost his wife in a car accident. He almost returned to sanity, taking the Chambler family under his wing and trying (and failing) to escape Martinez's group.
This is one of the reasons the show is so compelling. The characters are very well-written. Rick is a good guy, for the most part, but he makes mistakes. He also does things that "good guys" wouldn't do, like leave that hiker to his own fate i episode 3.12, only to return later to the hiker's mutilated body and take his backpack. He's had to come to terms with the fact that he can't save everyone so he's only concerned with saving the people he cares about. And he doesn't care about any of the Alexandrians (except maybe Jessie, and he just executed her husband).
Rick and the Governor do have a lot in common. Although I don't see Rick keeping heads in fishtanks. Then again, Rick still has Carl and Judith (who may or may not be his). The Governor lost his whole family. Such a tragedy might be enough to push Rick completely over the edge.
I think Rick is doing what he believes he has to do. He isn’t a villain, but he is damaged; they all are. At this point, he believes weakness will only get people killed, so he isn’t willing to risk it anymore.
I was told that Rick gets even darker, if the show follows the comic arc. I don’t mind so much...darkness doesn’t necessarily prevent me from liking a character.