Lol so you’re one of the Meltdown/Deathmatch contributors eh? Shame on you 
Just another reason why high XP yields per kill would be a bad thing, IMO
I think this would promote less team synergy and more kill happy playstyles. I only go 1-on-1 when I know I can win the fight, or when I’m forced into it and have no means of escape. When I’m matched with randoms I use my markers and try to isolate priority targets like healers or the dreaded Galilea, and I build even more then I would when playing with a party.
But you can’t win 'em all, if you lack team synergy chances are no matter how skilled you matched group is you’re gonna lose so sometimes you have to take the chance and try to surprise the enemy team with aggression and push them back, blindsiding can cause panic but it’s a very high risk tactic that’s only worth attempting when you know you’re outmatched and have to do something drastic to turn the tide of battle. In this example, if you fail and the XP yield for kills was higher then every death you suffer would give the enemy team a huge advantage, on the other hand if you succeed then you’d outlevel everyone and be able to win the game in one foul swoop. Tactics and longevity of matches are why I keep playing this game 