WARNING: The following contains spoilers for Boruto: Naruto Next Generations Episode 172, "A Signature of Fear," now streaming on Crunchyroll.
The Boruto series has given most of Konoha's senior faces ample time to showcase their skills even as the new generation moves forward. The likes of Naruto, Sasuke and Sakura are being used not just as parents but also mentors in both the manga and anime, while Kakashi is taking on a teacher's role once more for Team 7 in order to level them up to match their predecessors.
Despite this, the franchise is continuing to sleep on one of its most powerful, veteran ninja in the form of Yamato, the shinobi who holds Hashirama Senju's DNA in him.
Yamato has a very tragic past. He was kidnapped along with many other kids as part of Orochimaru's tests to fuse the DNA of the First Hokage with humans. This was done to see if he could create someone who could perfect the Wood Release, which would allow him, as the master, to control Tailed Beasts. That project failed and while the other kids died, Yamato was taken in by the wicked Danzō and used for evil purposes in Root. He even attacked his Konoha colleague in Kakashi in order to get the Sharingan for Danzō, but eventually, he saw the light and became a hero, dropping the Kinoe identity and taking on the name of Tenzō. He'd work with Kakashi, the Third Hokage, and Itachi, going on to excel as one of Konoha's finest.
However, when Kaguya enacted her grand scheme in Naruto, the older Yamato was absorbed by Tobi and fed on, taken out of the franchise entirely. Fans were disappointed as they wanted to see him trying to get the Tailed Beasts back from her, as well as fighting the Ten-Tails; yet, he was just used as food for White Zetsu to power their plans. After the defeat, Tobi spat him out, and Yamato still hasn't really done much in Boruto since then.
In the latest episode, he's once more being used as Orochimaru's watchdog, policing the secret location of his lab as the villain tries to redeem himself. No one knows Orochimaru like Yamato, a former son, if you think of it that way, but this totally wastes the shinobi. We don't even see him in person here as Team 5 visits; instead, we just hear from a junior guard that he went to file a report with Naruto.
It makes no sense because Yamato is a pretty amazing teacher: he used his Wood Technique to help Naruto tame Kurama, the Nine-Tails inside him. Kakashi trusted him with Naruto's mentorship for a while and even though Yamato does pop in every now and then to work with Sasuke, Sakura or on missions with younger ones like Boruto, Sarada and Mitsuki, he feels like such a peripheral figure now.
What would make his presence so fitting right now is that Konohamaru and Mugino need his expertise to investigate the Hashirama Cell that Deepa and Victor have taken for Kara. There's no better ninja for this job than someone who has Hashirama's DNA in him. He should have been supervising this mission as the DNA was revealed to be part of Orochimaru's old work.
Even if Kara came after Yamato to study as a living specimen, he'd have a more pivotal role in the overall narrative than being a legend who remains in the background.