Changes I would like to see for ninja in Stormblood

[Fluffernuff]

I really feel I must reply to this, as it reeks of personal bias and has no hint of resource or fact to it. I don't like people requesting change based on misinformation or the like.

Throwing dagger is a rather weak 120 potency ranged attack for for 120 TP. rather lackluster, and overshadowed by mudras if they are off cooldown. Shouldnt need to use it much, but its absolutley perfect for ranged lulls (hiding behind X thing for mechanic Y) or even as something you throw out to engage. Hardly "useless" or "unused"

Fuma shuriken.... oh dear... I'm not the type to state things so shallowly or bluntly, but not a thing you said about Fuma shuriken was factual or correct. Aside from katon having higher potency IN AoE SITUATIONS. How DARE a skil that can hit multiple targets do more damage than an ability that only hits 1! HAX! I call HAX!!! In all seriousness though, AoE on Ninja is laughable, but shuriken has literally nothing to do with AoE.
No, the power of shuriken is it's the easiest and fastest Mudra, is ranged, and in a bubble (meaning no added effects like hypercharge or reqiuem), it's NIN's highest single potency ability... off the global cooldown. Sorry. i'f you're not using shuriken because it "says" 240 potency, you're simply not playing ninja well....at all. It's very much equivalent to a Tank not using CDs or a Healer refusing to use cleric stance.

Without a MCH or a BRD, Fuma should be your default and first option to use over other mudras. Raiton is superior only under the Kassasu crit. because Mudra failing/GCD clipping is a thing.

Not going to touch on shadewalker /smokescreen. If you don't see the value in allowing the Tank and other DPS do even more damage with no downsides, I don't know what else I could say to make you understand that.

Poisons- well.. I can half agree with your assessment. you can't ignore the 20% bonus damage, though forgetting to reapply it isn't a weakness of the job. its a lacking part on your end to remember, and a lacking part of the overall mechanics of the game. Seriously, poisons are HARDLY the only skill that gets removed from level sync. Tanks lose their tank stance and have to reapply them. Fix level sync first.
That part out of the way, there's alot of potential for poisons that we just cant capitalize on. one stance is a silence, the other is a stun. theyre off the global cooldown letting us "stance dance" better than both WAR AND healers, but no real choice between them. you pick one for a stun, stun the thing, and switch back to silence so you dont screw over the 3 CC timer. I want more variation to what the poisons apply.

Hyoton is useless in PvE. Binds in PvP however, are quite powerful. While PvP is a tacked-on and mostly an afterthought for FF14, simply removing that ability in PvP just because PvE exists woult ONLY harm ninja. its a net loss without compensation. I do not approve.

Now onto the more concerning thing... The "problem" that DoTs and Debuffs "dont last long enough and don't hit hard enough". Ok, I'll give you a rundown. the reason you lose DPS if you deviate from this is because that's the definition and application of a "rotation". a series of abilities used in order to maximize effectiveness.
While I do agree that "hitting like a truck" is SUPER satisfying, those DoTs you "have" to apply are HARDLY wet noodles. you reapply them BECAUSE they hit like a truck..... but more subtly... yknow... subtle... like ninjas are. you stabbed them somewhere and now they're bleeding out. sure, you didn't lop their arm off, but now their kidneys are failing...because you stole them.

just to put numbers and mechanics here for you;
Shadow Fang does 200 potency by itself, and has a 40potency DoT over 18s. DoTs tick for potency every 3s. math math math, we gett 200+ 40x6= 440 potency. thats a whole 80 more potency than Aeolian edge from behind! GASP! but... what about mutilate? you get that early! that has to be weaker! 60 potency and a 30 potency DoT over 30 seconds- math math math- 60+30x10= 360... the SAME as Aeolian edge!?
Now knowing that DoTs do more damage with an increased duration, you're effectively asking for HIGHER potency DoTs, which we just established are your hardest hitters, AND having the freedom to have a single burst damage attack? Move over, Monk, we have a NEW best DPS in town!

Honestly, I feel DoTs fit NIN as a class fantasy more than pulling out a mallet 3x your size and bonking people with it. The job and it's nuance are just a bit more expanded beyond your experience. Practice makes perfect. Honestly, people devote their LIVES to the art of the Ninja and still cannot master it. You must hone your mind AND your body...young grasshopper.