I have suggested this idea a while ago and I still think it's really good, when I say perks I don't necessarily mean physical items like the healer and chef kits but instead passive boost like you get slightly healed after you kill someone (vampire/lifesteal perk) or you become faster after you kill someone (rabbit/scorpion perk?) Things like that are just some examples but I would like to point to out that, there are many different ideas and topics you can take from other games like call of duty. Tell me your ideas in the replies below and what y'all think about this.