My suggestion spawns from this little bit of text from the explanation of attacking (the link you can click above the drop down for attack options on someone's page):

"If you are successful with an experience attack, you will receive a big bonus to regular experience gains from a fight."

When I fight a wild NPC during explore, I tend to get somewhere in the range of 190-240 EXP. After attacking someone for EXPERIENCE, though, I only got 216 EXP. The above text says you would receive a big bonus, though.

My suggestion is to be given more experience from a successful PVP attack for experience.