Let me start by saying that I am thoroughly excited about this elite specialization; I love the idea of it, and it's fun to play around with. It feels like it needs a little work here and there to tighten up its sense of cohesion, but I don't think much work needs to be done to do that tightening. That being said, I'm no mechanics guru; I'm sure some of these suggestions will require scrutiny and refinement if they're to be taken seriously. These are meant more to play to the feel of the specialization and give that feeling a purpose/feedback loop without drastically altering what already exists. These ideas were also based on limited exposure to the specialization, and not an extremely in-depth analysis.
SUGGESTIONS:
Hammer 3: Hammer 3 skills either need:
* an increased duration (maybe double the current?) to allow for other skills to be inserted into the pattern of building up for the grand finale,
* or the ability to generate or throw skill 3 element orbs during any existing animation (think like the instant-cast Arcane utilities skills, Arcane Wave and Arcane Blast).
Otherwise initiating the first hammer 3 skill leads the player into pushing through all elements in rapid order to fire them off, gating other skills behind cooldowns. In the current iteration, this feels a bit like throwing a stick into the spokes of a bike wheel; you can't use skills during, and are locked out of using skills afterward, until coming off of cooldowns. Which compounds with a similar issue involving the specialization's F5 mechanic.
Specialization Mechanic (F5): For the class F5 skill: cooldowns plus energy buildup leads to too much downtime; the class is built around this mechanic, and it is fairly difficult to integrate into play. There have been many suggestions provided by others to fix this, but it is the stand out "feels off" element of the specialization. Being able to resituate the Sphere, increase its duration, or modify its behavior in some way to make it feel more impactful/relevant to the specialization, will go a long way to addressing this issue.
Hammer Play General: The specialization is combo-centric; there are a few skills that induce spinning in their animations, and many other skills of this type elsewhere in the game induce whirl finishers when in effect; the hammer skills here (Hurricane of Pain, Air 2; Whirling Stones, Earth 2) do not. Additionally, the player's location should probably deal a minor amount of damage during the non-field spinning portion of Hurricane of Pain, as you know, they're spinning around like an idiot wielding a heavy, impactful object.
Visual Flavor Changes: Visually, I'd probably also update the specialization to show the Jade Sphere floating over one of the Elementalist's shoulders; out of combat, it returns to this position and in combat it moves to the locations where deployed. This will make the class more identifiable and add a touch of flavor, much like the Engineer's Scrapper gyros. This is visible in the art assets representing the class and wouldn't feel out of place.