Hello, I have some suggestions to hinder the murderous class.
I will tell you each suggestion and why.

1- Remove limit rave for assassins.
This leaves all assassins unprotected in their own rave.

2- Increase 5% hits from killer to killer.
This makes few assassins strong and as a result many of them will not be able to have the power to beat other classes.

3- Place all raves with only 1 type of drug.
This means that assassins do not easily get donated kills from friends, because without limit of rave and 1 type of drug, the account that will donate kill to one murderer is in danger of being killed by another.

4- Do not allow a killer to see if he is entering rave or whorehouse.
This makes it difficult for them to attack someone, as rave and whores have different locations to select the victim.

5- Swing the place to leave the rave.
This makes it difficult for those who use macro to escape to be beaten more easily.

Well these are my suggestions, if you like it I'm happy to have helped.