I don't believe the word "fair" should be used... Basically because Elite Dangerous isn't about fairness, it's about survival. However the word "balance" comes to my mind.
What about simply sharing? If teamwork is going to be encouraged then why couldn't a basic "assists" system be implemented? Would that break Elite lore?
I mean, basically bonuses for the kill shot, sure, but if a pilot has been pounding at something for 5 minutes, expending missiles and ammo for someone else to simply come in with one last shot and take everything seems a bit imbalanced to me.
Perhaps this:
First shot: minor reward multiplier
Kill shot: major reward multiplier
Highest damage inflicted: highest payout
All assisted damage: percentage payout
And then everyone gets a piece of the 'Conda-pie.
Would this be immersion or lore breaking? At best it would encourage team-play and MMO participation... which is something that seemingly many want.
And if someone doesn't wish to share, they can just go Solo Mode... but, then they would have to take down those ships all by their lonesome and that's hard... ugh.. wait.. no it isn't! Perhaps the problem is there... that NPC's are not hard to take down.
So increase the payout and split it up... not hard math to implement me thinks.
Oh and for all that is holy... make NPC ship fly and fight better, otherwise soon pilots will have combat so down pat that it won't be a challenge... and when that happens, interest begins to wane.