Current State of End-Game Contents - A Blog Post from A Japanese Player

[Amberion]

2. Knowing your class inside out(so that you have your job in muscle memory for example..)

That in no way means the mechanics are hard.

1. Memory

Most fights you don't need to memorize. Could change in the future though when more fights are added.

3. Being able to execute a number of mechanics which differ greatly from fight to fight(reaction time, not panicking, recovering from medium mistakes)

Those aren't either mechanics.

Also, I did not say all mechanics are that easy, just that the majority is the standard "walk out of marked area". And to me personally, that is easy.