I did not read the whole thread.
- you already have a system that works for this kind of thing : system index = sqrt(started in system over the last 30days)/sqrt(started in total universe over the last 30 days). Do the same for bounties : add a concord index. Just dont go with petty 1% with system index, use 10% instead ; and use weekly value not monthly : concord index = 10×sqrt(bounties given in system over the last 7 days)/sqrt(bounties given in universe over the last 7days). You can even use 3-day sliding window instead of 7.
- PVP having an effect is dumb. It will be abused, maybe with you not realizing for several months/years. You got the problem backward : interesting systems SHOULD trigger PVP. That can be done by putting a part of the taxes inside a lootable stuff( ESS?) . But DONT ■■■■■■■ MAKE IT ABUSABLE ON PURPOISE.