Initially, when chronoboon displacers were introduced (in the end of the classic), their main goal was to allow players to play the game after they collect all world buffs and before they go to raid. However, it destroyed world buffs PvP - it was one of the funniest aspect of world buffs and blizzard just removed it. So, i suggest to do 2 changes to chronoboon displacers, so they will still do their main goal (allow players to play between collecting world buffs and going to raid), but also will return world buffs pvp same as it was in classic:
- Make chronoboon displacer usable only in cities and raids.
- Make getting next buff possible only if other buffs not booned. If you already have boon effect, you will be unable to get any other world buffs.