Diablo 3 turned 10 years old recently. Due to this fact, developers from Blizzard Entertainment decided to answer questions from fans about the behind-the-scenes of the game's development. Among many interesting facts, one in particular draws attention. As it turns out, title was to include a competitive mode (PvP) inspired by League of Legends.
Fan curiosity was satisfied by Wyatt Cheng, who is currently working on Diablo Immortal. He admitted that several different PvP variants were considered during the production. There were plans for arena with four columns and asymmetrical gameplay, during which one player was to take the role of a powerful boss fighting four weaker characters.
Among the ideas for PvP there were also solutions typical for the MOBA genre - players would clash on the map divided into three roads, along which one could encounter turrets and monsters. Cheng mentioned that during the internal tests the mode was fun only when using predetermined characters. Introduction of player-created characters was causing problems. These ideas were abandoned due to design challenges and other priorities. Eventually the PvP mode was introduced to Diablo 3 only after its release, along with 1.0.7 update..
If you are interested in other aspects of Diablo 3's production, you can check out the thread on Reddit, where all posts with the developers' answers are gathered.