There are many, many examples of prophetic mantle not making a person perfect. I can't think of any that would suggest the contrary.
- Lehi complained of hardship over the broken bow
- Jonah tried to flee from God rather than go to Ninevah to preach and even after being convinced to go, was hardly stellar
- JS and the Kirtland Safety Society episode
- JS suffering from normal human failures in the interrim between the FV and the appearance of Moroni
Paul had heated arguments with other leaders of his day. We are told in Acts 15 that he and his good friend and fellow missionary, Barnabas, "had such a sharp disagreement that they parted company" (NIV). This was because Barnabas wanted to take John Mark along with them, and Paul didn't want to because John Mark had previously not shown himself to be totally dedicated. Paul and Barnabas split, with Barnabas taking John Mark and Paul taking Silas as a companion.
An even better example of disagreements, this time over doctrine, is shown in Galatians 2, where Paul, telling his side of the story, said, "But when Cephas [Peter] came to Antioch, I opposed him to his face, because he stood self-condemned". This was over the issue of whether gentile converts should become Jewish in order to be Christian. It was a very heated and controversial subject in the 1st century. Peter had gone to Antioch and was freely interacting with the Gentile converts, even eating with them. But then a group of Jews arrived who followed James' more Jewish view. Paul's words: "But after they came, he [Peter] drew back and kept himself separate [from the Gentiles] for fear of the circumcision faction. And the other Jews joined him in this hypocrisy, so that even Barnabas was led astray by their hypocrisy. But when I saw that they were not acting consistently with the truth of the gospel, I said to Cephas before them all..." and he launches into a monologue about being saved by grace, ending with the perfunctory, "for if justification comes through the law, then Christ died for nothing."
However, that is all academic among us who view prophets as mortal. I think if I were teaching this lesson (or obstructing it from the back row), I would not give a long list of examples. Instead, I would call upon the Psalm of Nephi (
https://www.lds.org/scriptures/bofm/2-ne/4.15-35) in order to illustrate that we are all in this life trying to become 'like' God in very individual ways, and that is just as true for Nephi as it is for everyone in this room. Therefore, what we are following is not other people, no matter their position, but God. People like Nephi offered a lot of good that could be emulated, and a lot of wise counsel that could be followed, but as a man, he still had is own demons to conquer, just like each of us.