The issue with creating bounties depending on a player's kill streak means that just because I'm on a 5 kill streak, I'd have a bounty on me but I might've gotten those 5 kills in the past 20 minutes and gone afk for the last 5 minutes for dinner or something silly like that. Whilst we could apply time into the code for the bounty system, it will never be perfect and players would then learn how to avoid the bounty system. Why would you want to kill a player, to take their bounty points? That'd mean that you're the next target...?
So instead, what you could do is make players create a bounty on a player's for a certain amount of points, I'm not sure which currency we would use as of now but that's not important. You would be able to create a bounty on a player or add onto their existing one, with a point cap of course otherwise that would be extremely silly. But this could start some sort of boosting ring or trading/selling points from one account to the other by doing this so not the best idea.
The other solution to create side tasks that are randomly assigned to players throughout the session. Here's a list of some things that could help increase the flow of PvPing a player you wouldn't usually PvP - but again, not sure on the sort of rewards that would be given, if any at all.
- Kill player X.
- Kill player X within 5 minutes (counts down to zero, then expires if not killed).
- Kill player X, 3 times.
- Kill player X, 3 times within 15 minutes (if they leave, the task is cancelled).
- Kill a player with the same kit as you.
- Kill a player with the Wizard kit.
- Kill a player that has the Samurai kit with the Wizard kit.
etc, etc...