Let's be honest, no matter how valid your argument is about people joining just for experience without actually contributing (or actively letting themselves be killed), nothing can really be done about it without it being some sort of scorched-earth solution. At best, they could only possibly nerf 3rd place exp but significantly buff 1st place to actually be enticing to put an effort (y'know, effort like watching your maps and score, and knowing wtf Undead Redemption and Hallowed Ground icons on enemies are- just saw a MCH blow their LB on a PLD who had his LB active for like 4-5 seconds already, SMH) to win.

But really, since these sort of issues don't really happen on the JP side of things, and their players actually have an incentive to be there outside of "I'm just here for the exp;" they absolutely will not nerf exp to penalize them just because we have the lowest-common denominator players on our side of the puddle that will actively be a detriment to their entire team so long as it means they get their daily exp faster.