I think a good system to implement in 4.0 would be the addition of pvp fates. Something that does not involve a queue, except the timer for the fate to pop, and could involve deathmatch or objective play. Use a system similar to level sync which you could toggle on once you are in the fate and will not be switched off until the completion of the fate. This would help alleviate some boredom in between queues and can also start to bring open world pvp to ffxiv.