Gust slashes change was about 200 overall dps which is a significant, albeit very very very underwhelming change for ninja. I would argue that the Sam changes equate to far less than 200 dps over the fight. However, since this thread is about Sam issues I don't think comparing it to the most shafted melee dps who obviously needs help is useful, so I'll leave it at that.
While I do love quality of life changes (And I cannot deny Sam was buffed, obviously) it doesn't end up changing Sam's position in the meta because they did not prevent you from reaching the maximum damage when you had experience with the fight. Tsubame having a cast is an inconvenience, not something that would lower your damage in most circumstances and if it did it was poor planning on your part. It's useful to be instant but also shows a glaring issue that since Tsubame is an ability on the GCD you now have to feel quite awkward as you sit through the entire 2.5 second gcd to use your next skill (Usually after Tsubame you've just used a Senei, meikyo etc so your kenki it probably too low to use multiple shintens).
In regards to Shoha; before the changes Shoha was around 0.2-0.3% of your damage and now I would not think it significantly higher as you merely gained 50 pot for every fishing window (so 500 potency over a fight, optimally) and that is if you are able to... "obtain" (Let's put it this way) when every server tick is, without losing your auto attack. The thing is here is if you can target the boss but cannot be in melee reach for 1-2 GCDs then you should be using Enpi, not Shoha (100 pot + 10 kenki with a shorter time per gain than a shoha stack) which means, for example, in a fight like e1 savage you get two useful meditate (>2 stacks) each fight. The exception here is if you would cancel a combo finisher or drop a buff to use enpi as meditate becomes the lesser of two evils.
Hagakure being back is nice but there are only three real uses for it; disposing of a sen you would need to overwrite otherwise, as you want to be at 3 sen when tsubame comes off cooldown, resetting sen as your raid buff window is coming up (i.e. after adds on e1) or lastly, using it at the end of the fight when you would not be able to build another Midare (End of fight <9 GCDS). Anything else is a big loss in damage as just because your Midare is lacking one of the buffs does not mean it is better to exchange that sen for 5-15 kenki. Hagakure serves it's purpose and I wasn't a mega fan of shinten spam so I don't think Hagakure needs any changes.
Changes I would like to see would likely be some kind of shoha stacking mechanism based on Iaijutsu as this would both provide a constant use for the animation as well as provide a possibly more significant shift in damage. If we were to go beyond that, 2 tsubame charges (Even if one doesn't begin to charge until the fight starts) would also alleviate a lot of drifting issues Samurai experiences with the raid buff window, which is what Meikyo's 60->55 sec cd was meant to help with. This would be an additional 1200 potency over the entire fight, or less than 2 potency per second in a ten minute encounter.
I don't need Samurai to be a must pick or overpowered but it would be nice if it didn't take until 5.5 (just like stormblood) for samurai to not be considered a meme pick in PF. Black mages have managed it, why not us? Even if that means that playing Samurai at a top level has to become more difficult to compensate the higher damage.
My post is a bit lengthy, but I figured I'd write it out anyway.