4A games has said they will deliver a true single player metro experience, however they are exploring a multiplayer component that will fit in into the metro universe. If u havent read their statement here it is. I dont see anything wrong with 4A games giving us a badass single player campaign and a new multiplayer component.
Link: https://www.metrothegame.com/news/the-future-of-metro-4a-games-reveal-their-plans-for-the-series/