Another thing the PVP game needs is an attractant to players. Currently the worlds are HUGE and I mean HUGE. This disperses players who want to be far enough away to not be detected. However, this provides a game exciting while the player initially builds but seeing other players requires an active campaign. Right now the populations of servers is very low less than 10 players spread out over hundreds of km does not make for much chance they will be seen. The remote player can make everything he needs to live and even the glory of special armor is done in secret in dungeons.
Therefore there needs to be an attractant that makes players chance of getting specialized or buying specialized equipment or supplies a risk. The dungeons are not the answer at all unless the entire premise for the game is fight zombie NPC in the dungeons alone. There is a fine line and the devs will have to see what they want as too much a requirement for teaming up will push off the players who want the risk to survive while they build nice structures. Possibly a reward for structures above ground could be in order. Players building grand battlements have a higher chance of survival in their above ground home but there needs to be some functionality requirements.
Possibly the size of a farming lands for a large structure would be interesting. That is if you have a large structure above land you get certain crafting resources easier but the large structure requires you to have a corn field that is 75 by 75 blocks with hundreds of corn plants to sustain it. Add water requirement storage to the mix and you have a fight for resources.
None of this may ever be put in but the idea of making players have increased chances of conflict will help the PVP game. Having requirements for large structures such as farming and water will also help the raiding type conflict. Caution to the havign things destroyed while offline frustration is always in order for this line though. 
It can run in the background as you play without a problem 
