@xixaxap pick and choose always will have a negative effect on the current world.
While many enjoy PvP, most will risk their plan of doing voyage X or Tall Tales adventure if given the choice? I don't think so and therefore making one the friendly server and one the hyper aggressive version.
I play for the dynamic of a session, I lose I win, but still to this day and I have been playing since day one, I have no idea how people will respond on the seas. Fights are common, but with a bit of conversation, good positioning and forgiveness a truce is a very common aspect of my pirates life.
This dynamic is created by throwing everyone in the same sea and not splitting it in sections. Game modes need to compliment each other and not compete against one another by offering the same experiences and rewards. Not sure different modes were the best choice, but that ship sailed with the Arena.
In the Arena we experience the world in a different manner for a different set of rewards and a new faction. Any PvE mode should abide by that same principle, cause else it will change the nature of the Adventure mode in a negative manner. People shouting for PvE servers assume that everyone that likes the current servers are bloodthirsty pirate hunters, while there also others to consider that enjoy the mystery, the balance that is in the game between the players that kill you regardless, the players out to steal your treasure when ever given the chance, the players that like playing nice and the players like myself that switch their roles based on the situation. This dynamic is fragile and I believe is the main attraction of the game, at least for me.
There are tons of PvE games, there tons of PvP games and there are very little games that provide the experience that this game does. It is why I don't want to mess around with it just to have more pirates around... I rather have a smaller community, which holds on to the vision Rare started out with, the mystery and excitement of seeing sails on the horizon, than alter it for the fame, money and glory of a huge player base.
Predictability would cause me to lose all interest and for many core players I believe that is also true. I am a legend Athena 10 for months now and I get asked the question why I still play fairly often. It is the adventure, mystery and tales. The teams message with the tall tales is spot on and a PvE server would diminish its value by removing the largest wild card, the players.
I played WoW in vanilla till wotlk and if you think world open PvP was the same after they made changes to the dynamic. You are very wrong. Open world PvP in WoW died off, it had battle grounds, instances and raids and the biggest community to keep players. Occassionally a side would organize and attack a capital, which took hours to setup and an additional couple to execute and some random spots here and there that were contested like ZG island due to raiders clashing near the buff sight.
The WoW approach is not going to improve the quality of the Sea of Thieves experience.