In order of importance...
  1. More to deliberately build towards (rather than gain merely as byproduct) in the mid-term, e.g. between rotational strings and RoF/Bro/PB.

  2. Highly flexible rotations with initially simple targets but tremendous nuance by the time one reaches optimal high-level play, especially given the context above. These may originally seem forgiving but should ultimately instead feel precise (with many forking and intersecting rotational pathways with a hefty situational factors and changeability). Choices should be deliberate, but failed plans should allow you to adapt to new ones.

  3. Great aesthetic flow. The skills should look like they really do chain into each skill available after this. If that takes using a whole lot of conditional skills, so be it.

  4. Varying speed, be it by complex control of a (far more polished) GL- or stance-like mechanic, different skills causing different %GCD lengths (e.g. from 40 to 100%, conditionally or baseline), the creation of buffs from shared resource systems, or even by the implementation of a granular Stamina resource around which to vary between accelerated and slightly delayed rotational strings. This should be fairly integral to the 2nd point above.