I enjoy the killstreak update along with many others - mostly positive feedback regarding the feature. However, there are some adjustments I'd like to see implemented.
1) Re-add killstreak during tournament - Not sure why KS was removed from tournament in the first place. It recognizes people with a strong tournament performance, and with a bracket system killstreaks are inevitable. Another option would be to make tournament killstreak separate from regular wildy KS.
2) Allow KS to be saved when logged out - People have a life outside of this game, and it's difficult to stay in the game for hours to continue their KS mission.
3) Extend killstreak milestones (20 instead of 10) - with border pking and active tournaments, it's not rare nowadays for people to surpass 10+ killstreaks.
4) Remove killstreak limit - every 10 killstreaks above 20 (if implement the above change), a server announcement via pk chat will announce, "Humans is currently on a 30/40/50 killstreak, come to level x to end his streak!"
5) Add location to the killstreak message - "Humans is currently on a 30/40/50 killstreak, come to LEVEL X to end his streak!". If you add wildy level to the killstreak message, pkers will be able to locate the person with the killstreak and hunt them.
Ultimately, there is no harm in implementing any of these features. The killstreak system does not reward any monetary incentives in-game thus does not affect the economy directly. It is more of a recognition for active pkers who are dedicated in earning momentary fame. This is a psychological motivation for people to PK and extend their streak.