Pete, I agree with you somewhat.

Michael has Vito's intelligence, courage, and violence. However, he does not know how to blend them as Vito knew and did. So, I conclude that, to a large extent, he simply mimics Vito.

As he sits on his estate during the last scene of II, he contemplates (of course, we don't know) what he has done and also, perhaps, his future. Vito would never do that.

Michael can never escape the sin of fratricide. In III, that fratricide comes crashing down on him. That crashing is beginning to happen at the end of II.