If progress is tracked and there is an indicator that you'd satisfied all requirements for full experience gain, why continue? If you know that nothing you do beyond a certain point would increase your reward be it exp, conquest points or a chance at spoils, you're staring the reason people went AFK right in the face.
If it's so easy to satisfy all the requirements, then you make it harder. Or you just plainly don't cap it; if they complete the requirement then they do another. I mean, these solutions seem to stare one in the face. I really don't think you need me to spell these things out if you'll take a second to think about them.
Right, but the point is that it doesn't work well with or without the cap in campaign or WoE, respectively.
If there is a cap on performance points as there is in campaign, you do what you need to do to reach cap and then reset your campaign status to get more or go afk if you can't be bothered to scour the zone for mobs that people kited off to solo. If there is no cap like in WoE, people will want to go on jobs that give them the best chance to place higher than others.
I agree that the system is flawed, but adjusting it to level the playing field is essentially giving everyone the chance to either cap points as fast as the next person(where capped) or accrue as many points as the next person(where uncapped) so that they have an even chance to achieve 1st place. Again, if you're going to give everyone an even chance to get top tier loot, why not just give everyone the same chance for satisfying a general participation requirement. For all intents and purposes, it's the same thing without the fuss of having to come up with some elaborate system of handicapping or penalties.
Rewarding players for performance while setting up a system that is supposed to maintain even performance across the board is a nonsense approach to barance.