This game needs XP sharing system. This system will stop kill stealing by players from players, by NPCs from players, by players from NPCs, and will stop bluenoobs from farming deathclaws with the help from their stronger friends.
1. The amount of XP is based on damage dealt.
This is just to determine how big is your contribution in killing a critter.
2. Basic XP amount for killing a critter remains the same.
So there's no situation where you get more XP because you hit your target, healed it, and hit it more. Again, this is just to calculate shares.
3. XP is gained only after a critter is killed.
Obviously, you have to finish your job. Not like in Arcanum.
4. Only the damage that takes HP above 0 is taken into account.
Finishing off knocked out humanoids isn't much of a combat contribution. Same for scoring high damage crits on critters with low HP.
EXAMPLE 1:
Party of 2 players encounters a rat. Rat is worth 25 XP, and has 6 HP. Player A hits the rat for 5 HP. Next, player B hits the rat for 10 HP. Rat is dead. Player A gets (5/6)*25 XP, player B gets (1/6)*25 XP.
EXAMPLE 2:
A lone player encounters raiders and a caravan. One raider has 100 HP. The player hits the raider for 110 HP thus knocking him out. Next, a caravan guard finishes off the the raider. The raider is dead. Player gets 100% of the XP.
EXAMPLE 3:
Party of 2 players encounters a raider and a caravan. The raider has 100 HP and is worth 100 XP.
Player A hits the raider for 40 HP. Raider has 60 HP left.
Player B hits the raider for 30 HP. Raider has 30 HP left.
Caravan guard hits the raider for 20 HP. Raider has 10 HP left.
Raider uses a stimpak, and recovers 20 HP. He now has 30 HP left.
Player A misses.
Player B hits the raider for 20 HP. Raider has 10 HP left.
Caravan guard hits the raider for 20 HP. The raider is now knocked out with -10 HP.
Player C enters the encounter, decides to be funny, and uses FA on the raider. Raider recovers 20 HP. He now has 10 HP.
Player A hits the raider for 9999 damage. Raider is killed.
Player A gets (50/130)*100 XP.
Player B gets (50/130)*100 XP.
Player C gets 60 XP for healing the raider.
This wouldn't interfere with the current XP diminishing system. Simply, your share of XP would be further adjusted based on your personal kill count.
How hard would it be to implement?
Discuss, point out flaws.