I mainly play MMORPG for PVP and a big fan of open-world PVP. I am with the bounty system. I like the castle siege map of Elder Scrolls online I want a map like that most people will engage for endgame contents. Also, I want open pvp region all around the map setting PVP rewards according to level like defeating the opponent gives currency or gear in addition I also want some PVP-related quest all around the map for better rewards. My idea is to have players all around the map so we can enjoy PVP as well as enjoy the rewards. Don't worry I didn't forget the PvE player for them PVP free area with world boss, dungeon, raid, etc can be set. And MMORPG is incomplete without a duel, arena, battleground [small and big scale]. Also I want an open arena where people can watch the fight.
Open World PvP is a must for every MMORPG. Of course, there should be some restrictions in order to prevent the game being ruined by some people. It will be good if in the starting areas (lets say up to lvl 5-20, depending on max lvl in the game) there is no PvP at all. Also, there must be a restriction that higher lvl players cannot attack lower lvl players (I think 5lvl difference is OK). Of course, if lower lvl player attacks higher lvl player the second one can attack and kill him.
I also think that duels between allies should be possible for training etc.
edit: My post is general, not especially addressed to you.