The way I see it, Ninjutsu mechanics have not yet been reworked to fit the trend of other classes for this expansion. Specifically, 'streamlining' to make them more accessible and easier to play. Thus I can only guess that SE is still working on finalizing an overhaul for the class.
However, despite what SE will internally come to conclude, I would like to share my personal opinion of the main problem, from me playing the class as is: Jutsus are extremely underwhelming.
1) The potencies/effects are low and weak. They also do not feel rewarding. Compared to for example Monk buffs, Bard procs, etc. they are weak in both balance, and psychology.
2) The hidden recast timers on Jutsus. Awful awful mechanic. And hidden.
3) The chance of actual failure (bunny). "Sure blm can also fail in their rotation" yes but they don't literally get made fun of by the game for it. And if they get their rotation right they are "worth 1.5 ninjas dps".
To fix this, ideally the Jutsus should be able to impersonate the following traits:
1) Does not require a lock-on to cast. Similar to Apex Arrow of bard, but with much reduced range and width, so can be theorycrafted as single-target, melee dps.
2) All come with at least 1 additional effect. For example, elemental DoTs, debuff that can be exploded with next jutse, various combo effects depending on next jutsu cast, while reducing recast timers of all jutsus with successful combo chains. Thus inheriting and impersonating the "mudra" type logic, but at a larger scale. Yet different from traditional Combo potencies, as it is technically a never-ending, unfixed combo train.
3) The Bunny. Perhaps make it trigger 5 second CD instead of full 20 second Ninjutsu CD, while reducing recast timers of all jutsus. Or just redesign it.
4) (lack of) Ultimate-Jutsu. Firstly, Ten Chi Jin is much more tedious than say triple-cast, barrage, while being lackluster psychologically. While technically it is op when paired with Bunshin, in actual practice you have to manually sync the CDs, the Ninki Gauge, Ninjutsu recast timers, raid buff timers, it is not a flowing, enjoyable experience. And it does not make you feel like a magical ninja. Ideally it should additionally serve to provide utility similar to Requiescat, making all your jutsus ranged while under its effects, lasting longer but less potent (thus less pressure to sync perfectly with Bunshin and all the raid buffs). Thus feeling like an "ultimate" jutsu. Edit: Shuriken being a ranged attack should be upgrade to multiple-Shuriken under "ultimate" effect. Be it a single proc or time-based ultimate effect. Also, moving cancels Ten Chi Jin which is annoying, as brought up by many other players.
5) Recast timers and the Ninki gauge. Atm they are only weakly correlated, awkwardly linked. The Huton buff should also not warrant such a large energy indicator. Just in general, the whole logical structure has not beauty nor form to it. It's just a bunch of criss-crossing procs and a mess of things to keep in mind. While not very impersonating the average image of ninja. If you change the terms and the visuals a bit, could be any other class using lots of resources. Could be a mage class. Could be a monster. It's just underwhelming.
6) Hypothetical idea: Rework away the potency increase modifiers in Kassatsu and Ten Chi Jin to be more innate within the jutsus themselves as outlined above, or more external via passive procs and automatic triggers based on the Ninki gauge, with the prior (current) Ninki-based actions to become percentage-chance based triggers. Ninjas already have to mash so many buttons manually. Your hellfrog summon coming to automatically aid you every now and then is just reasonable. And introducing some luck-based, chance-based, merry happy-go-lucky type playstyle mechanics also fits the rogue/ninja characterization.
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Ninja also suffers in these additional areas:
4) Trick Attack. Some people say 10% dps increase is very useful. I say that it has less duration than some other raid buffs, is not actually a buff so is only useful for 1 target, requires Suiton aka. long build-up to cast (unlike for example monk and drg just 1-button instant), and psychologically, isn't as shiny as for example Drg buffs. It has a (hypothetical) 60 second CD which is shorter than other buffs, but a well-placed, well-synced buff with 50% more duration and timed with burn phases is arguably more valuable than a random 10% increase every now and then.
5) Shade Shift. Compared to bards who get a heal increase, debuff negation, raid-wide damage decrease, and also a raid buff, this ability is just awkward while partially overlapping with Bloodbath. It's also got a long CD. Feint is technically useful, but is less straightforward than direct damage reduce, and not as reliable as purposefully designed raid-saver CDs meant to catch tankbusters.
6) Shukuchi. While a stackable teleport is useful, it's more like a must-have nowadays for melee dps seeing how the new encounters are. Moreso, it's a targeted teleport so it cannot be used like a panic button similar to Brd's repelling shot, or used as a stress-free gap-closer via targeted action as with some other classes. Bard did away with flaming shot a long time ago because SE decided landscape-targeting abilities are really, not likable for classes already having lots of button-mashing. So why this design for Shukuchi still? Also it's not impersonating enough of a ninja characterization.
Hypothetical improvement: make it cast on press instead of mouse-click. Sync it with hide (though the low-level job quests will have to be redesigned as it uses this mechanic).
Edit: 7) Mug. Awkward placement of a skill. Needn't say more, prior sections made my point already.
All in all, even with the few aforementioned problems and possible changes, it will be a metric heap-ton of discussion, theorycrafting, testing, then possibly new animations and coding on SE's part, and post-development quality-checking to make sure everything is compatible with everything e.g. all past quests, dungeons, etc. So even if SE is already working on what efficient and slimmed-down a fix as they could, it's already a lot of work.
Thus the delay is understandable. However, this only increases expectations for one of the more keystone classes of any RPG. So please fix Ninja.
Thanks.