I have been a part of many, many types of MMORPG's over the years, whether they were Open world, Sandbox, whatever classification you you bring up I have most likely been a part of it. It goes all the way back to Ultima Online, Dark Age of Camelot, City of Heros, DC Universe, Age of Conan and everything in between all the way up to Conan Exiles, Gloria Victis, Life is Feudal and so on. So I have seem many many failures in the realm of PvP. One unsolved puzzle in super hero type games seems to be the PvP aspect because of the balancing issues with the powers, I can understand the issue because pairing a few powers together from a few players can create a dominating force, not only that but having the ability to upgrade those powers along the way through leveling, buying upgrades, Drops and so on can also provide a player with a great advantage over a lot of other players.
So...here is some idea's for a successful (What I consider successful) start when CoT implements PvP into the game.
#1. Open world PvP, This by far seems to the be most successful and loved by all players in games that I have played most recently. The idea of being able to log in and get into immediate action is what large number of players want these days, because lets face it, once you are capped on level and towards the end game this is the style of PvP that keeps players logging in daily even when the most hardcore player only has say 30 minutes to an hour to play. On the same token, there will need to be provided a safe zone or a few to keep the other players safe who just love the story line quests, or just PvE grouping. My idea, Have the higher tier zones...i.e. level 40 - 50 that you have to log into to get to large scale end game content, but also have it a PvP zone where players can fight for the right to farm a boss area. Not only that but a large portion of the map just a mass PvP zone.
#2. Players also want some recognition for being out there defending or hunting down villains in PvP..aka other players. There should be some thought to impliment a point based system, example: A level 40 player kills a level 50 player in a PvP zone, that lower level player will receive points based on the difficulty of him taking down a higher player. These point then could be spent once a lot have been accumulated on gear, or special powers to that can only be used in assisting him a PvP zone. Similar to the Realm Point system in Dark Age of Camelot. You could call it Fame, or Renown points. Also a continually updated point list on a web site somewhere would be helpful in keeps players out there and in the PvP zones, it's drive towards a goal.
#3. PvP controlled areas for Guild or Clans. This is another idea to keep players out in the PvP zones. Areas that Guilds, Clans, whatever you want to call them in game, that players can control to obtain materials for crafting better armors, mods to amplify their powers and so forth. I have never seen this idea in a Super Hero game and would like to. It would definitely give it a unique twist.
#4. Resistances and attack bonuses.! With a game like this where a player can potentially be attacked on an X, y, and Z, angles. I would like to see the potential for powers to be potentially cancelled by other players as a form of crowd control, if a player is flying overhead a tank type character, who only has jump that battle will not go so well, unless that tank has the ability to pull the flying player to the ground somehow. You can see this will get into the balancing issues that will come about in the early stages of the game.
I could go on and on because I really enjoy PvP in most games and I hope this game will have better more in-depth PvP action.