What needs to be addressed first, in order for the game to be properly fair and for Fdev to achieve something without nerfing the damn game again until there's nothing left but a husk shell, is to look at what's missing from this bounty mission-stacking. I'm not against finding something that you can maximize by looking for weak points in a wealth-returning task. I'm pointing out something that if this was a real life scenario, the other mission givers will be looking to see if anyone else has a bounty on the same guy and then consolidating the reward into a sort of general Galaxy-wide bounty, knowing that the player is going to try to claim from the several mission givers simultaneously. The game would have to use an algorithm to search for already accepted missions for a generated mission, and then avoid producing duplicates while at the same time increasing the reward for the bounty- this would reflect a real-world scenario of bounty givers acknowledging that a target already has a bounty and they could just accept that there's no need to issue a further one, since it's already being dealt with in that way. They could perhaps all add to the bounty-pot for the same target, but you would only get ONE payout, because of the galactic-wide system keeping a record of a bounty already on a target.
Fdev could implement a diminished reward for claiming bounties for a kill you already completed elsewhere. The reason I say diminished and not 'removed' is because it should be allowed for you to claim more than one bounty for the same target- because yes, if two factions want the same guy dead and they're willing to pay, then you should get paid from both sources, HOWEVER.. players are using this to exploit the game <sigh> so as to "stack" up more money. They are only doing exclusively multiple bounties, which, in such an anarchistic universe as ED, that seems legit and profitable, but from the NPC's/game's point of view it is exploiting the fact that you are getting FULL pay off multiple sources for the same kill - which should really only grant ONE full pay for that kill, and then the subsequently attained bounty missions for that same target should check their computer, see that you picked up that same bounty elsewhere and then they will tell you that you already claimed "the bounty"!
Furthermore, what's to say another player or NPC can't go to the other guy and say "hey, that target is dead, see..I' killed him and I'm here to claim." then the bounty giver would have no choice but to pay out. Then you finally arrive, saying "Hey I'm here, finally to collect my bounty" And the giver says, "And I'm Santa Claus, GetTFOutta here. I already paid out."
After all, isnt the game offering multiple bounties for the same guy? This is what's being exploited; This wouldn't be correct- there should just be ONE Wide bounty for each target, which can be collected at a station that has the tech to utilise a database for this purpose. This helps to maintain realistic simulation, prevent the game being polluted- by other content being ignored, resulting in faction-based consequences shifting the soft-powerplay incorrectly and other integral factors that are alive in the game from being unfairly altered as a result of players exploiting one area of gameplay.
THEN.... combat rewards in general should be looked at. <phew!>