It looks like you're new here. If you want to get involved, click one of these buttons!
The world of Fallen Earth is unique and is actually a real world representation of the Grand Canyon in the future. There are over 11,000 square kilometres. This game has a focus in both PVE and PVP. If you are interested in PvPing there are four arena style game types: Deathmatch, Survival, Assault and Capture the Flag.
Our second recommendation is Defiance, a science fiction-themed persistent world MMO third-person shooter. This MMO is based off the SyFy show of the same name so it has a strong storyline. Defiance takes place on a terraformed Earth several decades into the future. In the game you play as either a human or an alien. There are several ways to not only customize your character but also your weapons, armor, and special abilities.
In Defiance you play as an ark hunter, which is basically a treasure bounty hunter. You are a specialist in survival, combat and tracking. At the start of the game, you arrive in the San Francisco Bay Area in search of valuable Votan technology. There are several ways you can participate in player versus player battles. In addition to the traditional team deathmatch and capture-and-hold modes, Defiance offers competitive multiplayer in a massive open-world mode known as Shadow War.
Our final recommendation is Planetside 2. Planetside 2 is free to play open world persistent MMOFPS. We wanted to point out the fact that this game is focused on PVP and does not have any PVE content.
But in terms of PVP you will be experiencing large scale battles between three factions, Terran Republic, New Conglomerate, and Va-new Sovereignty. In this game you will take part in a battle with thousands of other players. You will have access to both air and land vehicles to help you achieve your sides goals. There are six classes in the game: Light Assault, Heavy Assault, Combat Medic, Engineer, Infiltrator, and MAX. You mentioned that want a class that can DPS and Heal, so I think the combat medic would be a great fit. They are incredibly versatile and utilize rifle and healing grenades.