Now, this is a bit more subjective than all the other queries so far. However, if you want to get into the hardest content, sadly only some classes are viable. If you take the time to know and understand your class, you will do well. In the game in its current state, you can get into endgame content with pretty much any class. Instead, skank tanks are favoured as they can taunt and guard while being able to deal a good amount of damage. DPS and Healers are obviously useful but Tanks, not so much. In PvP, however, things are a little different. When it comes to DPS, you need to know your class and pull high numbers.1 Tanks and Healers are becoming increasingly more scarce and harder to fill for raid groups. If you want to get into endgame raiding, obviously Tank and Healer classes are going to be in more demand than DPS.