The Boruto series is hurtling towards its 4-year timeskip now and with the timeskip comes opportunities for characters to grow stronger. In Naruto, every character, during the timeskip, became incredibly strong and returned a brand new person. Given the fact that the Boruto timeskip is twice as long as the one in Naruto, its characters should become much stronger.
While there are certain characters who are guaranteed to grow stronger, certain others require special attention from the author. It goes without saying that the author has not been paying proper attention to some of the cast, and, as such, they require many power-ups to be relevant again.
6 Sarada Uchiha
Sarada Uchiha is the daughter of Sasuke and Sakura. Although she has incredible potential to become one of the strongest ninjas to ever live, Sarada is weak at the moment when compared to the likes of Boruto and Kawaki. She cannot compete against either of the two and if she aims to become the Hokage of the village, she needs to get much stronger.
Thankfully for her, there is a lot of time to grow in terms of strength and fans would like to see her return a different person after a 4-year timeskip. It would also bode well for her character if the author decides to focus more on her in the arcs. For the vast majority of Boruto, Sarada has been sidelined for characters like Boruto and Kawaki and that needs to change.
5 Mitsuki
Mitsuki is another essential character and certainly needs more attention in Boruto. He is a member of Team 7, just like Boruto and Sarada. However, just like Sarada, he hasn't received enough attention in the story so far. Mitsuki also possesses a lot of potential, which is clear from the fact that he was created by Orochimaru to be the perfect human and someone capable of surpassing even the Legendary Sannin.
Mitsuki's character is full of intrigue, however, he is not explored enough in the story. If he is to be relevant in the story, he certainly requires more power-ups.
4 Konohamaru
Perhaps one of the characters who require a power-up the most is Konohamaru. Konohamaru is the leader of Team 7 at the moment, but he is not a skilled leader, by the looks of it. He wants to follow his idol, Naruto Uzumaki, and become the Hokage of the village. However, sadly, Konohamaru has been treated extremely poorly in Boruto.
He has barely been a part of the story and has received even less attention than the likes of Mitsuki and Sarada. Konohamaru is also incredibly weak for someone who claims to be the captain of Team 7. All his students are likely stronger than him at the moment and that is a damning statement to make. He needs many power-ups to be relevant in Boruto again.
3 Sasuke Uchiha
Sasuke Uchiha is one of the most important characters in Boruto and, just like Naruto, he ended up losing a vast chunk of his powers after the fight against the Isshiki.
Sasuke has not, since then, been as important in the story, however, given how much fans love him, he has to play a major role sooner rather than later. He cannot do that with his current level of strength and, as such, would have to grow stronger. In order to grow stronger, Sasuke would require a power-up of some shape or form. Consequently, he could then protect the village in the absence of Naruto Uzumaki.
2 Shikadai Nara
Shikadai Nara is the son of Shikamaru and Temari and he's also a somewhat important character in Boruto. While the anime certainly does focus on him quite a bit, the manga does not at all. Shikamaru was a very important part of Naruto, yet his son, Shikadai, has not played any significant role so far.
He is out of his depth when compared to the Team 7 members and certainly requires a big power-up to be relevant in the story. Shikadai is a character that many fans like, however, the author needs to do him justice and make him a bit stronger or, at the very least, a bit more useful in the ongoing arcs of Boruto.
1 Himawari Uzumaki
Himawari is the daughter of Naruto and Hinata, and the sister of the protagonist, Boruto Uzumaki. She is a character with just as much potential as Boruto, if not more. Recently, it was even teased that she had some hidden power within herself that would make her as strong as characters like Daemon or Ada, or even the godly Otsutsuki. That said, Himawari has not played any major role in Boruto so far.
She has been sidelined for the vast majority of the series and it is time that the author focuses on her a bit more as well. Himawari would require being given the chance to showcase her power to the fullest if she is to be relevant in Boruto. Now that fans know she has a sleeping power within her, it is only a matter of time before she showcases an incredible power-up in Boruto.