Just wanted to preface this post with a statement that this is purely for constructive criticism and is intended to engage is positive feedback. Also, this is strictly from a PvP perspective.

Damage:
Fatecarver the skill is terrible for PvP due to positional desyncs that occur from the client and also has too long of a cast time. I suggest making the skill have execute damage and interruptible so that it has a use and counter play.

Tentacles the stamina execute morph should scale similar to Whirling Blades and not "up to 100% damage". IF the target is below 50% health have it do 100% more damage. The magicka morph was a positive change but still feels like it lacks damage.

Fulminating Rune as stated in the PTS week 3 notes, Zos never intended for the Arcanist to be a burst class. That being said, the class still needs pressure for damage. This skill and its morphs have too long durations for the tooltip damage to be effective. I suggest lowering the duration of the DoT to 8/10 seconds in order to add pressure.

Tide King's Gaze Ult The tracking on this skill is atrocious. I recommend increasing the AoE radius in order to make the skill more effective and useful over outside of class ults (DB/Meteor).

Sustain:
This class should have way better sustain purely from its passives alone but MOST people have sustain issues. The biggest reason I've noticed from my testing comes down to a single ability and its morphs.

Runemend this skill is entirely way too expensive. The HoT isnt very good when comparing it to other HoTs in the game but also the morph that reduces cost is simply not enough. Most players spam this skill in order to receive a HoT but also, more importantly, to generate crux in order to use for a burst heal from the shields. I truly think the the skill needs to be reworked so that each crux increases healing done/received and lower the cost of the skill by 20-30%.

Tidal Chakram this change appeared to be good on paper. The problem is the shield size. Even with Bastion I was only getting around a 6k shield which equates to roughly a 990 HoT if you consume 3 crux. Just a terrible tooltip and not a very good skill.

FPS:

Im not sure if this is just a PTS issue but I continually drop frames while testing skills with other players. I recommend maybe reducing the flashiness of some of the skills to reduce performance issues when it goes live.

OVERALL: I really love the way the class is aesthetically. But the class has some major issues. The lack of damage will pigeonhole the class into running cheese proc sets and the class has major sustain issues. I enjoy the new design of a somewhat mini game with the crux system but it also causes issues with bar space. If anyone else has suggestions for changes please leave them below!