I would have liked to see Clemenza in addition to Pentangeli and not instead of him. Clemenza and Pentangeli are two different characters and there is no reason why they could not co-exist. It is true that the Pentangeli character was invented by Copolla after castellano made demands that Copolla could not agree upon. But they were so different in their nature. Clemenza was one of the closest persons to the family, probably after Tom Hagen. After the shooting incident with Vito, you can see Clemenza acting like a real family member. He was concerned about michael, he gave him a lot of advice before michael killed solozzo. Clemenza also had the instincts of a mobster, he was personally involved in killing a Don in the elevator and also Carlo.
On the other hand Pentangeli was a more of a funny guy and very lovable. We do not see him kill anyone. We do not know what qualities he had to qualify as a mobster. But you can definitely see that he was one of the guys who was always loyal to the family (at this moment I can see you jumping with the question - what about the testimony against michael? ). The answer to that is simple. Yes he betrayed michael, but he was not like Tessio or Carlo or Fredo. Pentangeli was a victim of michael's games, and in a way michael was the architect for his own betrayal. Pentangeli was among the old timers. He was proud to be associated with the family. He was against drugs, that Vito was also against. Even tom acknowledges his role before in organising the family into capos and soldiers, before he forces Pentangeli to commit suicide. He says to michael "Your father never trusted Hyman Roth". That was prophetic and at the same time was something that I believe even clemenza would advice michael in his early days. Both Clemenza and Pentangeli believed in Vito's way of running the family and probably never understood michael's mind.


I agree with SC. Having Clemenza betray michael would be shocking, similar to Fredo's murder by michael. I am happy that the idea was abandoned.