If Don Corleone did not choose Michael Corleone to become Boss of the Corleone Family, who do you think would have been a good choice for Don Corleone to choose as Boss of the Corleone Family?

I think, if Don Corleone did not choose Michael to become Boss of the Corleone Family, he could have chosen Sal Tessio. Sal was the smartest of the Corleone Family's most powerful Caporegimes, and without the help of Don Corleone, Michael would have never known that Sal was conspiring with Don Barzini to murder him.

This is a difficult question because succession was Vito's biggest problem:
As we know from the novel, he didn't consider Fredo a serious candidate because Fredo lacked force. GF and II portrayed him as too stupid to be a Don. Sonny had force, but he lacked judgment and couldn't control his temper. And Vito didn't want Michael to be directly involved in running the Family.
I doubt that Vito would have turned the reins over to either Tessio or Clemenza. According to the novel, he kept both of them apart, in separate territories, so they wouldn't be tempted to plot against him. He kept Clemenza close to him because Clemenza needed reining-in periodically, but Tessio had a freer hand, and some outsiders didn't even know he was affiliated with Vito. Tessio seemed more intelligent. But, I'm guessing, Tessio's distance from Vito on a day-to-day basis would have counted against him: he might not have had the loyalty of those closest to the Don, and Clemenza may have opposed him.
I think that, if Vito had had his way, Michael would have gotten a law degree, entered politics, and become "Senator Corleone, Governor Corleone..." Then Michael would have worked to "legitimize" the Family business--perhaps by pushing for legalized gambling, or by channeling the Don's labor rackets payoffs into his political organization. Sonny would have been the head of an ever-diminishing "traditional" Mafia business. As the outright "illegitimate" Family activities got smaller, so would the risk from Sonny's hotheadedness.

I think he would have chosen Tom Hagen even he has not italian origins if he could, in case he would have done than against the Cosa Nostra rules, he would have used all his influences and power to persuade the other families to do that, after all he was a consigliere(you have to be a made man to be consigliere and to be a made man you have to have italian origins) even though Tom knew he could never afford to be boss because he was not italian. But I think Vito would have helped Tom to become the boss because he is clever, close mouth, and more loyal than most of the italian members(Freddo) and I think that is upon the origins you have, Vito didn`t care about this stuff, he would rather choose the skills and intelligence over the italian origins(it doesn`t mean you are the right person to run the family just because of that).

If Michael wouldn`t have gotten into the "family business", Freddo was weak and stupid(And I guess Vito knew somehow Freddo would betray the family someday even he wasn`t sure), Sonny as a Don is dangerous for the family, Connie, well, she is a woman and Vito didn`t want women for this, Tessio would be a traitor someday, Clemenza is not so clever but he is loyal.
The only one who left is Tom Hagen.
He is clever and loyal, and he is a lawyer. As a lawyer he can find the way to make some move without getting in trouble.The rest had more possibilities to get in, even having Tom as a consigliere being a lawyer, the boss decides what to do, not always follows the advicer.
Tom Hagen being the boss could run the family without trouble and he could make the decisions by his own, even he would have a consigliere for him as a rule.

I`m sure Vito could have changed that "rule" which doesn`t allow Tom to be the boss.

Whoever runs the family have to be a good Don, it shouldn`t matter who the boss is.

Tom Hagen would have been the best choice.

I think he would have chosen Sonny (had he lived) with Hagen as consigliere. I dont think he would have gone outside his bloodlines.

It seems to me like the line "I knew Santino would have to go through this," or something like that, which Vito says in the garden to Michael, to me that indicates that he was going to hand over the reigns over to Sonny even though he knew it might not be the smartest decision. Almost like he knew what was going to happen but he just hoped it wouldnt.

I think some of you misunderstood my question. I did not ask who Don Corleone may have chosen to become Boss of the Corleone Family, if he did not choose Michael Corleone to become Boss of the Corleone Family - I asked who do you think would have been a good choice for Don Corleone to choose to become Boss of the Corleone Family.

I don't think Don Corleone would have chosen Sal Tessio to become Boss of the Corleone Family, but, in my opinion, he is the best choice Don Corleone could have chosen to become Boss of the Corleone Family if he did not choose Michael to become Boss of the Corleone Family.

You are overestimating Tom Hagen, Don Pappo Napolitano. Tom should have known that the Five Families were only "quiet" because they wanted to make Sonny Corleone think that the Corleone Family was winning the Five Families war. Mario Puzo explains, in The Godfather the novel, that Tom thinks this is a trick that Genco Abbandando would have never fallen for.

I think I got you since the get-go, I still think Vito would choose Tom Hagen against bloodline. He is the most trusted man Vito has.

He knew Salvatore was too smart, and wont take too long to start selling up the yeyo, getting into Barzinis interests and selling uo the Corleone family.
Petie Clemenza was way too impulsive, he would replyed to the other families incursions into their territories and move them out while the muscle was in hes side.
Maybe in both of these options the Corleone family would have been divided into little families and street gangs.

Santino would be the natural first choice.

I would say Clemenza would be the second choice, as he was strong and after all, he brought Vito into that life.

I will rephrase my original question. Who would you choose as Boss of the Corleone Family, if you could not choose Michael Corleone as Boss of the Corleone Family?

Tom Hagen, even he is german-irish. He is a lawyer, he is clever and close mouth.He is the best choice I could have.

Noooooooooo way! (Just Kidding)

I would say: Frank Pentangely, in that age he was no one, but he has the aptitudes!

Frankie Pentangeli was not intelligent enough to become Boss of what the Corleone Family had become over the many years, because of Michael Corleone. Frankie was a street Boss, he was more suited to the "smaller" options available to him, e.g. gambling, etc.

Frankie Five Angels is a good...
But I don't he's a good choice as a Don...

Yeah... But sometimes you just need to be a wise old fox sanked in wine to manage things rigth! Michael was more a buissnesman, not a Capo...