We spoke to this just last month in one of our dev diaries (dated 5/15):
Quote Originally Posted by BB_Effiluna View Post
PVP
PVP is an important feature that is still on our roadmap. PVP has been delayed compared to previous plans, but it has not been cancelled. Due to its meaning for the game, a variety of ideas about how to design PVP for TSO were discussed and evaluated. There are different approaches which resulted in a couple of versions during the processes of design, balancing, and coding. Right now, we have to make the complex decision of which version is the best solution for TSO in terms of gameplay, balancing, and also regarding the technical aspects. Additionally, each complex feature needs an intense testing phase. At the end of the day, these are some of the reasons why we cannot tell you an ETA right now, but we want to assure you PVP is still on the roadmap.