Does the prevalence of intercessions and pardons in exchange for blood money, and the like, make light of intentional killing in brawls and other situations, and encourage those who wish to kill?

Whoever intentionally kills a believer unjustly must offer sincere repentance and surrender himself to the guardians of the slain, who have the choice between retribution (qisas), accepting blood money (diyah), or pardoning. Islamic Sharia came as a middle ground between the law of the Jews, which mandated retribution without pardon, and the law of the Christians, which mandated pardon without retribution. Pardon is originally superior, unless its harm outweighs its benefit, such as when the perpetrator is an aggressor and an oppressor, and pardoning him is feared to lead to his continued injustice. In such a case, retribution is superior, and the one who pardons would not be acting as a reformer.