Not every job should be simple to play. To be very clear, simple isn't bad, but complex isn't bad either. A well designed mmo should have simpler and complex jobs both. It's actually important to have both, so that the most amount of people can play together, depending on what kind of gameplay experience they like or prefer.

For people who prefer a simpler job, you have WAR for tanking, WHM for healing, SAM for melee dps, DNC for ranged and RDM for casters. There's a simpler option in every role, allowing anyone to play every role. Other jobs are more complex for people who prefer that gameplay.

One of the things long term players have been strongly critical of in Shadowbringers was how drastically they over simplifed more complex jobs and the entire tanking and healing roles. We're actually very unhappy with what they've done to so many jobs this expansion, over simplifying everything, when we already had simpler jobs for people to play.