WARNING: The following contains major spoilers for Boruto: Naruto Next Generations Chapter #50, by Masashi Kishimoto, Mikio Ikemoto and Ukyo Kodachi, available now in English from Viz Media.
The Boruto manga initially seemed like it was going to make Kawaki one of series' biggest characters. He destroyed Konoha, challenged Boruto and revealed he killed Naruto, the Hokage, in a flash-forward, with the story then showing his journey in the present as a vessel for the ruthless alien, Isshiki. However, while it tries to paint him as an innocent victim who holds enormous potential, the latest chapter proves that Kawaki is nothing more than a wasted and very disappointing plot device.
Kawaki hasn't been doing much of anything apart from wandering around Konoha and being treated like Naruto's step-son. Sure, he trains and bonds with Boruto and the others a bit, but he's never really made into his own character, as the franchise wants to keep his past vague. He's the mysterious kid Isshiki's meant to reincarnate in, but as he accepts Naruto's family, there isn't much growth and sadly, not much of a personality developed. He skulks around, coming off like a wannabe young Sasuke, but one would think seeing Naruto almost sacrifice himself for Kawaki would be more reason to have him playing a bigger role.
Instead, when he's brought back to Konoha and his Karma mark is gone due to Koji Kashin drawing Isshiki out, Kawaki strangely takes a backseat. He hasn't been trained as a proper ninja so he brings nothing to the table, and it seems like all he was is a Karma seal. It doesn't do him justice, especially if we're to believe he's going to be a villain. The series also does the obvious with Naruto and the mentor-student team of Sasuke and Boruto battling Isshiki, ignoring Kawaki who should have played an integral part in this fight. Hiding him away doesn't feel right at all; despite his Karma being defunct, had he been properly integrated into Team 7, Kawaki wouldn't feel like a trivial and peripheral figure.
As it stands, he plays a cosmetic role, simply there for Isshiki to come and brand again, which feels very bland. He acts robotic and hasn't meshed well with anyone else. There's no emotional attachment as he's guarded by Shikamaru and other Konoha ninjas. The chemistry is off and when the manga tries to force banter, the dynamic doesn't feel right.
At least Sasuke had personality when he was an angsty, scowling teen, but sadly, Kawaki's been totally mishandled in this aspect. He should have been given ample time in the spotlight rather than the focus being shifted to Boruto going after Isshiki, all so Naruto's son could prove he's living up to the Hokage and Sasuke's legacy. This approach would have better set Kawaki's future up and added a lot more gravity to the war that's going on right now in a secret dimension as Isshiki plans to hunt the kid down again.