Maybe we should invite a paleontologist to give us an opinion on the comparison you make. If I understand you correctly you are saying that the paleontological record of humans and their precursors is more mysterious or more difficult to understand than that of other animals. I don't think that this is true.
Fossil records are very incomplete.
Some kinds of animals are more likely to leave fossil remains than others, however, and that often makes for a more complete record of some kinds of animals than of others. Aside from this factor I think the fossil record for humans is quite comparable to that of other animals.