When the universal goal of the Children of Israel is taken into consideration their road is not that "rough" since they play a significant and positive role in human development.
The two books should be renamed for clarification.
1. Rename the Old Testament as "The History of the Jews."
2. Rename the New Testament as "The life and teachings of Jesus the Savior, the man the Jews reject."
Perhaps in this way, some might understand a little more clearly why Christians might agree with Jews regarding the two books, and the two faiths.
1. No Jew accepts Jesus as the Messiah. When someone makes that faith commitment, they become Christian.
2. It is not possible for someone to be both Christian and Jewish.
3. Jews reject Jesus as the Messiah because he didn't fulfill Jewish expectations of the Messiah.
The Hebrew Bible (called the Old Testament by the non-Jewish world) is not proof for anything in the New Testament regarding a Messiah.
My view? Christians should ignore the Old Testament and accept the New Testament.