My ideas for player vs player.

each player is given an island to protect. island starts at level 1 and gives a few basic resources once a week and has room for 2 generals to camp there. island can be upgraded to level 5 giving room for 10 generals and generating expert resources once a week.
island is defended by regular generals and troops. so players will need more of both.
also island can be defended by traps and battlements. which are bought in a new building on main island. also upgradeable to level 5 with access to better traps etc.
traps are hidden on island and kill some troops. battlements are reinforced walls that give bonuses to defending troops.
every week that you own the island you will get resources plus a 10% bonus compunding each week untill you hit a maximum so it is in your best interest to keep the island well defended. this requires frequent logging in to game to refresh troops.
you can buy maps to a random player's island with map pieces. each one allows you to attack their island for 1 week. just like adventure timer. you can also buy maps to specific players islands if your guild is at war with other player's guild.
attacking another player looks and feels like a regular adventure except oponents can refill general's troops.
if you win you take lots of resources and prevent other player from getting those resources that week.
the resources you win are based on island level, how long since island was taken last, and your level vs other player's level. so if you are level 40 and opponent is level 20 you will get less resources than if you defeated a level 50 opponent. and attacking a level 5 island gives more than level 1
high end traps cost gems, regular cost wood, stones etc. same with battlements.
balancing: island gives resources but costs troops both to defend and attack. and costs resources for traps etc. so should have net neutral effect on economy.
massive losses of troops might result in more gems purchases as people settle old scores etc.
anyone have any ideas?

You got more PvP in mind than what BB understands what PvP actually means, but after having read "having an island to protect [...] with regular gens and troops [...]" was pretty much the point where I cam to the conclusion that it's far too different from what BB has currently in mind and setup and would need to invest a bunch of time and resources to make that happen....which by conclusion of said observation is unlikely to happen.

I think we can all agree (minus BB, fanboys, trolls and other defenders), that PvP in this game is non existant and there are far better PvP games to be played than this stationary click and wait game. Although I'm split on different games and having different classes like "mage vs soldier" and it can work, my truest definition of PvP is a shooter, where everyone has access to the exact same things but the skill alone makes the difference, not the class, not the level, nothing else.