The momment there is an strict way one class has to be played COMPLEXITY is out of the question. Someone might have solved the complex question "what is the rightest way to play class A??" The rest just read the answer to that question and trained themselves to do it propperly like good monkeys.
Yes it's easy, becuase GW2 is truly complex so most of us would simply suck at it if it offfered a true degree of difficulty. Real life combat isn't about spreadsheets, equations and optimal theoretical solutions, it is about preplaning sure, but mostly about execution (timing and proper tactical fast thinking) this is what GW2 attemted to do and it succeeds in doing so. You (and I sometimes) might prefer the comfortable spreadsheet-uber-plan-to-beat-them-all-anytime, the sad reality is that no plan will survive contact with the enemy; This is so true in PVP, but even in PvE it bears quite a lot of truth since "aggro" in GW is unpredictable, but I am sure that makes GW more simple than WoW in your eyes ... well we just have antonimous definitions of complexity.