Limit the number of proofs a character can gain in a week
While it's really awesome if someone can solo a World Boss, it ain't that awesome anymore if that player farms all the World Bosses solo while the rest of the server (the people who really need the proof to get better gear and must work together to achieve that) looses the access to that resource (except for high prices in Auction House) and need to wait on proof events...
If someone can solo World Bosses, he should be greatly rewarded, because it is a great achievement.
There only must be a limit on how much, so other server population also can take a share.
Limit the number of proofs per character to 15 a week.
I know, this will hit hard on the financials for those people who farm 50+ proofs a day.
But we live together on the server so we must share with each other.
And while i know this suggestion isn't perfect, it is a step in the right/fair direction and forces people to teamplay.