One doctrine that has been debated, even among Trinitarians, is that of the peccability or impeccability of Christ. While many Trinitarians such as Philip Schaff have affirmed that Christ could have sinned (i.e, was peccable with respect to his human nature), most do not.
Writing in defence of the impeccability of Christ, Anglican Darwell Stone wrote:
The doctrine of the impeccability of Christ does not impair the value of His human example. It has sometimes been urged that the resistance of Christ to temptation is of no value to us as an example, if it was impossible that he should fall. This argument rests on a failure to grasp the true nature of the example of Christ. If the example of Christ was that of a mere man, or if it was the example of one who possessed an independent centre of human personality, the objection would probably be of weight, because in that case any example to us of Christ’s life would simply be a kind of book or a kind of picture, and would be separated from ourselves. In such a case, the value of the example might depend on there being in it the same element of peccability which there is in us. The example of Christ is not of this kind. It is the example of one who not only shows the right course, but also imparts to men union with the life in which the example was given. Christ, as the second dam, as the source of the life which is in those who are sacramentally united to Him, gives the strength wherewith His own victory was won. Therefore, the example is to be judged from a wholly different point of view from that from which a merely human example would be judged. (Darwell Stone, Outlines of Christian Dogma [London: Longmans, Green, and Co., 1900], 79)
One can see many problems with Stone’s argumentation, including (1) perverting what it means Christ to be our example. In the view of those who hold to the peccability of Christ’s human nature (which I would argue is part-and-parcel of Latter-day Saint Christology) is that Christ was only our example against temptation and sin in outward appearance only, not in reality, as not being able to sin in the first place, His struggles were only a form of theological play-acting; (2) Stone has to poison the well by arguing that only a “mere man (psilos anthropos) Christology” allows for the peccability of Christ’s nature without any meaningful substantiation—what can be gratuitously asserted can be gratuitously denied and (3) ignores texts of the Bible which explicitly states that Christ was exactly like us in all things except that he never sinned, not that he could not have sinned:
For it is clear that he did not come to help angels, but the descendants of Abraham. Therefore he had to become like his brothers and sisters in every respect, so that he might be a merciful high priest in the service of God, to make a sacrifice of atonement for the sins of the people. (Heb 2:16-17 NRSV)
Since, then, we have a great high priest who has passed through the heavens, Jesus, the Son of God, let us hold fast to our confession. For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who in every respect has been tested as we are, yet without sin. Let us therefore approach the throne of grace with boldness, so that we may receive mercy and find grace to help in time of need. (Heb 4:14-16 NRSV)
If anything, Stone shows the gymnastics, both theological and exegetical, many Trinitarians engage in to support their Trinity model. Furthermore, it does show that Trinitarian Christology significantly downplays, if not just perverts, the true humanity of Jesus.
For a Latter-day Saint discussion of the humanity of Jesus and related topics, see, for e.g.:
