Let's Theorize a 5.1 Balance Patch.

[Shurrikhan]

...

Ninja
1. Bunshin reduced Ninki cost to 40. Cooldown removed.
2. Ten Chi Jin is an alternative Ninjutsu cast that doesn't consume current Mudras. GCD. Damaging Ninjutsu cast this way deal 50% more damage. 45second cooldown, 3 charges.
3. Throw Dagger does not interrupt combos or mudra combinations. Combos from any Mudra for additional potency and faster recast.

1. Depending on the potency you leave with Bunshin, wouldn't this then be your only viable option? This seems like taking TCJ off the cooldown and then somehow expecting Baha and Frog to compete with it still.
   
   
2. So you build Mudra and then release with TCJ instead of Ninjutsu, incurring a GCD cost but dealing additional damage, or you hit TCJ and briefly convert your mudras and your next (3?) Ninjutsu to partial GCDs?
   
   
3. How do these Mudra-Throwing Dagger combos work?

Samurai
1. Hagakure - Sen converts into Meditate stacks. Cooldown is now 60 seconds.
2. Tsubame Gaeshi - Only usable after Iaijutsu. Grants 1 meditate. 30 second cooldown. 300 potency. Removed from the GCD.
3. Shoha - Scaling changed to 100/150/250/400/600
4. Guren Senei - Cooldown reduced to 60 seconds.

1. That doesn't seem much of a potency buff, and quite unevenly distributed... Worse, it'd still be a potency loss to use. The old Hagakure, for instance, granted what would now be 768 oGCD potency per use. Yours would grant 200 (overcapping; last stack only) to 450 (best gains over last 3 stacks at +100/+150/+200).
   
   A Kasha or Gekko combo average an 405 effective potency per GCD. Kaiten Midare does an effective 944, granting almost 540 bonus potency even when including all its resource and opportunity costs. You would need to beat that to make the skill worth using. To make the skill useful for flexibility, it'd need to be almost exactly equal. For comparison, simply giving it 10 Kenki per Sen would grant a flat 384 bonus potency and giving it 15 would grant it 576, a mere 36 bonus potency that could be easily dismissed in favor of its more impactful benefits such as Sen-shearing.
   
   I, too, would like to see more frequent use from Shoha, but I personally feel like the Kenki itself is far more pivotal to our playstyle and from a much earlier level, and should be prioritized accordingly. Note also that these stacks would do absolutely nothing until level 80, unless Shoha is moved to an earlier position.
   
   
2. This wouldn't be a very significant buff, despite being more convoluted and, to most SAMs, likely less iconic. As you have no other ways to build Meditation in combat, save facing the same lower value per stack issue in Hagakure, you cannot assume that you'll get the full 200 potency of going from stack 4 to 5 each time atop the base 300 potency. With Hagakure at 60 seconds, you'd only generate 58 more potency than the current "trap" iteration of Hagakure, and then 150 and 200 from TG for at best another 950 oGCD potency per minute -- assuming the SAM can end every 30 seconds precisely with an Iajutsu. Keep in mind TG uses apply Kaiten for free, thus a K-Midare is a true 1200 potency, with only the average ppgcd cost against it. It is, therefore, worth 795 oGCD potency, further emphasized by raid (de)buff windows.

Red Mage
1. Embolden is now 60 second cooldown, 2 charge maximum, 10 second duration, 8% damage bonus to all damage.
2. Manafication is now just +80/80 Mana.

That'd be a significant loss to gameplay in the minds of most RDM mains, I'd imagine.

Summoner
1. Energy Siphon instead ends Trances and grants Ruin 4 charges.
2. Egi Assaults are moved to the GCD. Potency is increased. Sourced from the Summoner instead of the Pet.

1. Then what happens to Aetherflow abilities?
   
   
2. Aren't they already sourced from the Summoner? I could have sworn their "200 potency" deals the same damage as your 200-potency double-DoT Ruin III. I'll double check, though.

If BLM's Enhanced Sharpcast can have a guarantees a critical hit then I want that for SAM's Kaiten too and just increase kaiten recast time.

Let's be clear: it'd only guarantee a critical hit on an inferior skill which requires another inferior skill just to proc it. Fire I extends the AF phase, allowing for more Fire IV over time than if it weren't used, though not by any huge amount or to any massive gains now that we have Despair and such a long AF duration. Fire III (Firestarter procs) had likewise become increasingly situational. This would make the Fire III held more worth using outside of movement (especially now that Fire III is always free from UI3).

[Kabooa]

Ninja

Samurai

Red mage

Summoner

Ninja
I'll have to recheck. I assumed it still granted extra Ninki on hit. The idea being that Bunshin becomes sort of a hyper Huton window that you aim to maintain, but spend excess amounts on other Ninki skills.

You build your Mudra, use with TCJ, then use with Ninjutsu as well. TCJ being GCD just alleviates the clipping pressure (and sets up for the ninjutsu use as well).

Ten -> Enhanced Dagger -> Chi -> Enhanced Dagger -> Jin -> Enhanced Dagger. It doesn't serve to make ninjutsu better, it offers ninja some more manipulation tools as well as increased downtime-uptime. It's not necessarily a power buff - it's a usability buff. Not interrupting weaponskills means that if anything forces you off boss midcombo you can still generate ninki without dropping your main combo.

Samurai
Hagakure is meant to be an option, not a straight up use. However it's current implementation is only if delaying Tsubame is a greater offense than losing a Midare. This variant puts varying value between 1, 2, and 3. It isn't meant to be an always use option like previous Hagakure was, it's meant to be compelling choice when the situation arises that's rewarded properly. That said it's directly related to Shoha numbers so meh, you can tweak that for indirect adjustment.

Looks like it can all be number tweaked.

So we could easily just adjust Shoha and TG up and it's all gravy.

Red Mage
I mean, I suppose. I haven't asked all of them.

Summoner
Siphon is the AoE version. They still have Energy Drain. I should have specified that the abilities would be unhooked from each other. What this does is allow a Summoner to pop a trance during a transition window, store up some Ruin 4 for whatever use, but more importantly get the trance window rolling.

[Shurrikhan]

Ninja
I'll have to recheck. I assumed it still granted extra Ninki on hit. The idea being that Bunshin becomes sort of a hyper Huton window that you aim to maintain, but spend excess amounts on other Ninki skills.

My only point was that if you've relegated it to Ninki generation alone, you'd effectively be spending 8 Ninki per 15 seconds just to look cool, as Bunshin only regenerates 28-32 and would now cost 40. If it still has potency, however, you'd be spending only 8 Ninki for it, which would be beyond overpowered. As you generate 6 Ninki per strike, you'd generate 48 Ninki per Bunshin. Subtracting its effective cost, you'd generate 16 Ninki per Bunshin or roughly 64 per minute. That would mean you only get to use any skill other Ninki skill once every 75 seconds. I imagine Ninjas would quickly get so sick of it they'd want it removed outright, nuked, buried, exhumed, desecrated, spat on, and buried again. I could certainly be wrong, though.

Hagakure is meant to be an option, not a straight up use. However it's current implementation is only if delaying Tsubame is a greater offense than losing a Midare. This variant puts varying value between 1, 2, and 3. It isn't meant to be an always use option like previous Hagakure was, it's meant to be compelling choice when the situation arises that's rewarded properly. That said it's directly related to Shoha numbers so meh, you can tweak that for indirect adjustment.

I just don't understand why you'd make a level 58, 60, and 76 skills all dependent upon one other skill. 3 means of generation, with capping conflict between each other due to increased value per stack per stack (yes, potency/stack^2; not a typo), all for one ability that's far from central to the class (and, at present, only unlocked at level 80). Shouldn't Shoha be better working to tie into the 58, 60, and 76 skills rather than their value all being back-loaded by Shoha?

Let me spitball an alternative real quick:

1. Third Eye will now guarantee parry against attacks targeted against you while reducing damage taken from universal ("raidwide") attacks until having mitigated up to 15% of your HP.
2. New trait: Live by the Sword - Damage mitigated by parrying, dodging, or other means, is stored as latent HP. Parry strength increased by 33%. This latent HP begins to drain at 1% max HP per second after 10 seconds.
3. New trait: Art of the Sword - Merciful Eyes, Hissatsu: Gyoten, Hissatsu: Yaten, and Hissatsu: Seigan can now ignore a portion of their cooldowns by consuming Kenki proportionate to their remaining recast times to a maximum of 20.
4. Hissatsu: Gyoten no longer has a default Kenki cost. It now deals 150 potency on a 30-second cooldown. Gyoten may now be used on an ally, freeing the ally from Binds and Heavy effects and intercepting damage against them to a maximum of 30% of your effective HP. Strikes which would deal more than that amount will not be diverted. Damage diverted in this manner may be absorbed and counted towards Live by the Sword.
5. Hissatsu: Yaten no longer has a default Kenki cost. It now deals 150 potency on a 30-second cooldown.
6. Merciful Eyes now generates 400 potency of healing in addition to consuming up to 20% latent HP. No longer requires Eyes Opened. 30 second cooldown.
7. Hissatsu: Seigan no longer requires Eyes Opened. Consumes 20 Kenki to deal 260 potency. 30-second cooldown. Consumes latent HP for further damage, to a maximum of up to 20% latent HP at a time. (If one managed to bank 40% latent HP, you could double-Seigan at 60 Kenki cost and still come out ahead of Shinten in efficiency, though you'd be well behind Senei or Shoha (see below).)
8. As of level 74, Meditate also generates latent HP at 10% HP per tick.
9. Shoha can consume latent HP without limit. Costs 20. As efficient when used to consume 20% or less latent HP as Seigan, but more efficient than Seigan at higher levels, since it only costs Kenki once to make use of the full amount of latent HP.
10. Voila! You now have a deeper survival/counter-attack system that feeds intuitively into more in-combat Shoha casts. Any big raid damage nukes + Third Eye = Shoha. Save up a Shoha for TA window and then grab one more useful TA towards its end for a parting Seigan. And you can be that one jerk of a raid member who insists on attempting to finish the last 3% of the Savage boss's HP on his own by way of self-healing over jump mechanics.
11. Hagakure (for context), now grants 15 Kenki per Sen and has a cooldown of 30 seconds which may be rushed by Art of the Sword (at up to 192 potency cost -- costly, but better than even 3 lost ticks of Kaiten-Higan or a delayed TG). The recast time is ignored when outside of combat and thus it can freely be used early.
12. Tsubame-Gaeshi (for context) remains as is, but has a 7-second period of leniency after any Iajutsu in which it may still be used without having to be a consecutive action, greatly delimiting SkS breakpoints for SAM.

Ten -> Enhanced Dagger -> Chi -> Enhanced Dagger -> Jin -> Enhanced Dagger. It doesn't serve to make ninjutsu better, it offers ninja some more manipulation tools as well as increased downtime-uptime. It's not necessarily a power buff - it's a usability buff. Not interrupting weaponskills means that if anything forces you off boss midcombo you can still generate ninki without dropping your main combo.

I guess I'm just curious why the same wasn't done for all the other weaponskills, while simply buffing Throwing Daggers themselves? (I'd argue that Meditation, Piercing Talon, and Enpi could also use slight to significant buffs.) With current oGCD times, Suiton-Kassatsu-Hyosho or TCJ itself is usually long enough to cover any periods of forced melee downtime.

[Kabooa]

My only point was that if you've relegated it to Ninki generation alone, you'd effectively be spending 8 Ninki per 15 seconds just to look cool, as Bunshin only regenerates 28-32 and would now cost 40. If it still has potency, however, you'd be spending only 8 Ninki for it, which would be beyond overpowered. As you generate 6 Ninki per strike, you'd generate 48 Ninki per Bunshin. Subtracting its effective cost, you'd generate 16 Ninki per Bunshin or roughly 64 per minute. That would mean you only get to use any skill other Ninki skill once every 75 seconds. I imagine Ninjas would quickly get so sick of it they'd want it removed outright, nuked, buried, exhumed, desecrated, spat on, and buried again. I could certainly be wrong, though.

Ninja at 80 generate 8 per strike and 4 from Bunshin. This means in a Bunshin Window Ninja would gain 72 - 84 Ninki.

Throw Dagger compared to the other job skills is more iconic, as Ninja has been the 'throwing job' in many incarnations. You can certainly buff the other job skills if you want, but here it felt like a fitting way to grant some flexibility to Ninja's kit as well as provide a weaving tool in heavy mudra segments.

Regarding Samurai, I've got no dog in this fight.