It is true that he wanted to honour his father, and that is a merit. When he said he didn't want to kill Yaakov until his father died, he shows some of the respect he had for him. He didn't want to make him further suffer. Due to his respect for his father, his offspring were numerous and important for the development of world history.

The Torah reveals that Esav didn't notice for a time that his parents didn't like his women and that they didn't want Yaakov to marry daughters of Kenaan. That is why this question arises: Why didn't Esav notice these things before? Obviously Esav couldn't discern what the will of his parents was, nor did he know the reason for their high morale that he had been taught since childhood. His senses for the things of the Eternal were not open. His spiritual eyes and ears were blocked and his heart was insensitive to divine hints, even if these came from his parents.

A very serious thing had to happen for him to find out what displeased his parents, not to mention what displeased the Eternal - something totally unimportant for Esav. Since his life only revolved around what he could take advantage of, he only found out when it was too late.