I'm not positive as to why Titans & Hunters give 25 pts per kill and Warlocks award 75 pts. However, I have my own little theory. The title of mutiplayer is Crucible. If anyone is familiar with history the Crucible is a play written about the Salem witch trials. During these trials supposed "witches" or "warlocks" would be prosecuted and burned at the stake. This is my theory of why killing warlocks awards more points since the Crucible is essentially a witch hunt.