Sounds like Aristotle and scholasticism. So why do I need Objectivism if I have 2000 years of Aristotle and scholasticism to draw on? It's far more developed and well though-out than Objectivism.
You were able to reject conclusions coming from Objectivism. If a conclusion is reached by Objectivist reasoning then it should be compelling to reason, at least to the reasoning faculty of an Objectivist. His reason should assent to it. But you say the conclusions can be ignored. Maybe Objectivism has little to do with reason in the first place, and more to do with sophistry, polemics or fiction-writing.
It’s hard to determine the exact point where Objectivism derails, but IMO it is in ethics and morals where a certain amount of reality is ignored by the more dogmatic objectivists. It is a nontrivial task as they themselves acknowlege: e.g., what is “good”? It is the one of the highest level, most abstract concepts built on a large base of underlying concepts.