[[ This has been sitting in my inbox for almost a month and I just keep meaning to answer it, lskdfjlksdjf. I am here now.
Of course, this question is slightly objective. It could mean a good decision (for himself), a good decision (for others), and so on. For the sake of this ask, I’m going to assume you mean, did Sasuke make a good decision for himself to leave the village before the timeskip.
And my answer is yes.
Although the story did make it clear it was actually healthy for Sasuke at the time to stay with Team 7 and slowly give up on wanting to kill Itachi, that all falls apart very, very quickly. Sasuke is still having trouble controlling his curse seal, Itachi’s returned and made a complete fool out of Sasuke, his inferiority/superiority complex with Naruto is rearing its head, and Kakashi, the closest thing he had to a parental figure, has suddenly turned on him and demanded Sasuke completely give up his goal or he won’t train him (Hypocrite– since Kakashi’s known this was his goal since the beginning of the series).
Then the Sound 4, a group of people all with Curse Seals, show up and completely wipe the floor with him. All it serves to do is show Sasuke how weak he truly is at this time. Kakashi has already been pushing Sasuke extremely hard, going as far as to break him out of the hospital to train, something seen as a positive sign of determination.
And where did that get Sasuke? Nowhere. He still got his ass kicked, so clearly he needs a teacher who is not Kakashi, because Kakashi is not cutting it and has already threatened to stop training him completely. Kakashi is useless to him now.
And through all this, Sasuke doesn’t really want to hurt Naruto and Sakura. He leaves because he’s not getting the training he needs, and because he needs to cut Naruto and Sakura off. For their protection. If they won’t chase after him, he won’t do anything.
Of course, if you want the POV of the village, or of the rest of T7, none of those people will think Sasuke leaving was a good idea/decision. But Sasuke needed to move forward, and he’d reached a point in time where staying at the village meant stagnating. ]]
[[ Also HufflePuff. Putting Sasuke in Slytherin is too stereotypical and is usually based off of fandom/exaggerated traits that people think all Slytherin have. Most Uchiha do end up in Slytherin, to be fair, but not for the exaggerated negative traits people think Slytherin have. ]]
This is somewhat of a relief because I was slowly losing my shit over the fact Sasuke has the sword (and a new scabbard) in his reference sheet for The Last. I pulled up an anime reference sheet first but I generally don’t trust those, not with how many edits they made to Kishimoto’s original sketches.
Right, so, he clearly still has Kusanagi. As in he picked it back up, it was given back to him, etc etc, one can kind of freely headcanon how he got his sword back but he made a point of traveling with it and get the scabbard replaced with an identical one.
This, however raises the question of…..when did he choose to give this one up? More importantly, why? What would drive Sasuke to pick up an entirely new sword? We’ve seen how durable and useful his Kusanagi is, what’s so good about the sword he’s using that he gave up his previous one completely?
My running theory, for the when, at least, is he started with the new sword around the time of his novel, but, the only image I can find by Kishimoto doesn’t even properly depict a sword.
(That still doesn’t answer why, I guess that is lost to the ages.)
Unfortunately this is….unclear. It certainly seems to look like his new sword, as the scabbard doesn’t have the black line running through it like his Kusanagi did. We also have little way of telling if this end of the sword is the hilt or the blade, ugh. (It does extend slightly under his cloak, between the foot and the cat, so this is a sword scabbard.)
Now, about that new sword….
AFAIK, Sasuke’s novel (the original text) doesn’t go into detail about the sword. Not in the sense of “this sword is new and different.” It only mentions when he’s using it. So for someone who doesn’t know Sasuke has switched swords they could very well visualize him using his original Kusanagi.
But the animated version of Sasuke Shinden absolutely depicts his Adult Sword. Granted, I did choose not to watch Sasuke Shinden because they shifted story elements around. I did some googling and was completely unable to find screenshots/stills of Sasuke’s scabbard during the duration of his animated novel (if he even has one in the animated version).
More about the scabbard….
Top Photo: Official Reference sheet of Sasuke from Boruto The Movie. His scabbard is a dark red.
Middle Photo: Official Kishimoto Illustration of Sasuke’s scabbard during his novel. It is a dark blue/purple.
Bottom Photo: Screenshot of Sasuke mid-fight with Kinshiki in Boruto The Movie. Scabbard appears Maroon– but this is due to the overall color palette in the scene. The scabbard matches the top photo I twould be a dark red.
Now for some colors from Ikemoto, Boruto’s current artist.
This sword has a black scabbard.
Ikemoto has currently updated Sasuke with a new outfit and this probably means a new scabbard.
Conclusion: Sasuke just changes scabbards pretty often.
The sword itself is exactly the same, just with a shiny new scabbard. Makes sense, since he loves to change outfits, too.
Now….what exactly is this sword? I honestly just keep calling it Kusanagi because that’s what I’m used to, but this sword doesn’t have a name and as outline above, we have no insight as to why Sasuke chose it and replaced his previous chokuto with this one.
Let’s see what the actual Kusanagi sword looks like…
Okay, alright, now Sasuke’s adult sword.
((…. I am this close to ignoring Sasuke’s present day sword for my blog and instead pretending he still has the chokutō because the timeline of the chokutō to current sword post war is shady as fuck and confusing. ))
UchihaSavior 
