My preference for world buffs is this.
A personal toy you can purchase with accommodations once you become exalted with that particular faction.
The buffs are individual. Not raid wide.
The toys have a 24 hour cooldown and are account wide as the rep grind on multiple characters would discourage people from playing Alts.
Basically if you work hard enough you can get a buff in a bottle so you don’t have to run around the world for an hour every week. For those who would rather not spend that time rep grinding they can get buffs the old fashion way (paying a Hunter 10g to get into his DM N instance)
24 hour cooldown solves the paladins in the open world from blowing you up in 1 second instead of 2 issue but also allows you to have world buffs for multiple raids. (Currently you’d use world buffs for bwl and then bottle it for next week instead of using it on your MC raid the following day)