Serco Dominion / Itani space:
Killer is native Victim is a foreigner and has signed up for military: no penalties for killing.
Killer is a foreigner Victim is native and has signed up for military : -500 std loss
Killer is native or foreigner, Victim has not signed up for military:
victim is POS/local nation space -1100 if the victim is native -800 if it is a stranger
victim is admired/local nation space -1000 if the victim is native -500 if it is a stranger
victim is respected/local nation space -250 if the victim is native -100 if it is a stranger

Added: Both killer and victim are native:
both have signed up for military no std loss
killer have signed up for military, victim has not : -1100 std loss for admired or POS, -500 for respect
killer have not signed up for military, victim has: -1000 std loss for admired or POS, -400 for respect
none of them have signed up for military: -1100 std loss for POS, -1000 for admired -250 for respect

Military status of the target should appear on the HUD

UIT: at least any kill of a UIT citizen in any corporate sector should decrease UIT standing in addition of local standing loss.
Victim local/UIT POS : -1100
Victim local/UIT admired : -1000
Victim local/UIT respected : -600

Unmonitored sector / greyspace rules remain unchanged

EDITED:
With nahin remarks

+1. But what if a killer is native and the victim is native, both have signed up for the military? Or neither? There are a few other situations to work out, but this is definitely a good idea.

edited for missing situations

+1, this is a good quick fix for certain faction situations, especially serco/itani space.

If I remember correctly, Devs already said that these standings won't be something easy to get back like it is now.
If they reduce a lot the standing income per mission, this idea here won't be a good one anymore. (IMHO)

Its been suggested before.
I was thinking using 2 tables to look up an adjustment based on faction - one table for the majors and a second local table to handle all the minors.
A single table might get to large to handle all the minor factions
Inclusion of the hive and player factions would also severely increase the table size as well

anyway +1 to making an adjustment based on combatant factions

Personally I would also like to see an overall "reputation" added to the system Perhaps as an average of all the factions. Characters with a bad reputation should be generally mistrusted and faction should be slower to go up. Corvus would be the opposite as they would tend to trust someone with a bad rep a lot quicker then the local care bear

I can't easily link to my previous posts on this right now, but I've mentioned elsewhere the intention to expand Temp KoS to better handle PvP killing in protected locations. This will basically place another "layer" on top of the existing faction system that's more specific to player-killing (and forgiveness), with the potential for lengthy durations to add up.

Wait... we have a faction system? When was that added?

HAR HAR HAR.