So i had an idea on how to make world bosses an epicenter of both PvP and PvE. Here's the jist of it:
1. The gurubashi arena dude spawns a super chest that contains, among the normal gurubashi arena loot, a special item.
2. Players go in and loot the chest, that item is used to spawn one of the world bosses. It has 30 minutes duration. These chests spawn ever 30 minutes.
3. Lets asume there are 5 world bosses, until all 5 world bosses are down the super chest will continue to spawn every half an hour. Guilds and pugs will be fighting over that chest to loot it.
4. Whoever summons the world boss gets the loot, attibuted to all players in the same raid group as the summoner at the spawn moment. So joetheninja leaving midfight won't matter.
5. Resetting the boss despawns it, players must go back to the arena and loot the chest again. Remember that chests will continue to spawn until all 5 bosses are dead.
-"Spawning" means a way to engage the boss, not necessarily make it appear, some bosses may be super-invincible and that item simply makes them "vulnerable" and thus killable, another boss may simply turn from friendly to hostile... Any mechanic can be used so it makes sense lore-wise.
-This forces players to engage in FFA PvP over the chest and bosses, players are encouraged to follow the raids and sabotage their attempts so they can get another chance at the chest. I believe this could make for alot of fun and drama over these world bosses.
-Loot has to matter, some heroic token or a mount or title or rare materials or something. This has to have a good enough reward so players come back every week to do it in masses.
-There should be daily quests with conquest-cap-bonus or honour rewards to kill players at the chest or an engaged world boss. Have as many people go out and fight other players, weekly quests for those bosses, archievements like "kill all 5 world bosses in the same day", "disrupt 10 world boss attempts", "loot the chest", "kill 100 players near the chest", etc... This could lead to alot of groups forming, guilds competing and an overall increase in social activity (with lots of player deaths :D).