As someone, who's been maining Hayato, Kanna & Beast Tamer, playing all of them at a end game level.
(Having solo'd Black Mage on each of them, and being part of a Kalos party)
While i agree with the above class specific issues for Kanna, i want to add a severe issue that plagues these classes, is the lack of receiving regular updates that other classes get.
Several of Kanna's issues have already been fixed for other classes in prior patches, similarly applying these fixes to Kanna (in addition to Hayato & Beast Tamer) is the least amount of attention i think these classes deserve. Here would be some of the more significant ones:
1. Cooldown Alignment
Since Destiny, every class has become either 60/120sec or 90/180 cooldown cycle. Where at least their personal skills have no contradictions to this, meanwhile Kanna has:
Spirit's Domain (196sec),
Yuki (75sec),
Oni Lord's Legion (180sec cooldown, that doesn't start until the 60sec duration is over, so that it's effectively 240sec).
This is in addition to some of the important shared Sengoku branch skills being:
Sakuno's Blessing (240sec),
Sengoku Forces (120sec).
With the ability to get 2 stacks of Sakuno's Blessing, Kanna was effectively turned into a 196sec cycle class, which helped a bit, instead of having to delay Domain till Sakuno was off cooldown, but it's still far from optimal as it requires waiting for 2 stacks of Blessing before starting to do bosses or other stuff, and in 30min boss fight, have 2 of 10 bursts without Blessing, while also using Sengoku Force every 196sec instead of the possible 120 it could've if not for the contradictive cooldown cycles.
2. Action Delay Decreases
Kanna is a very clunky class to play, which is only tolerable because it has an animation-canceling skill, whereas all Korean classes continuously have improvements to their skill's action delay, Kanna does not receive any.
3. Key-hold down duration cut
Another thing is how cooldown burst skills, which require the key to be held for the duration of the skill, had their duration cut and got increased damage, if this was (properly) applied to Kanna's Vanquisher Charm, it would significantly improve the usability of the skill.
4. Cooldown(s) Being Applied at the Start
Taking an example from this patch's quality of life improvements to Ark's Endless Agony, where the cooldown was being changed to apply as soon the key was pressed and held down, instead of when the key is being released, is another thing that could significantly improve Kanna's Vanquisher Charm, being spent to charge Domain, and then waiting out the cooldown reusing it for burst. Likewise with the issue of Oni Lord's Legion where the 180sec cooldown, doesn't apply until the end of the 60sec duration.
In addition to these few significant issues, there have been several other small common quality of life things that could improve the class besides its damage. Such as upward mobility skills changes, aura-type skills not putting you in combat, and more.
Personally, i wouldn't mind playing a weaker job, if the said job were also well-maintained and fluid to play. But I'm instead watching how every other class gets small improvements that could apply to the classes i play without receiving them. This is adding insult to injury on all the class-specific issues Kanna, Hayato & Beast Tamer have.
(another example, would be how Beast Tamer was ignored in the last patch when Zero and Kinesis got their missing V skill, despite similarly missing one)
So just reviewing the common quality of life balance trends that have been applied to other classes and applying these to Kanna, Hayato & Beast Tamer could already improve both the damage and the experience playing these classes.
Took forever to get a forum account verified despite the message of how it would be within 24 hours, hence why this comment is added this late
