Tsuyu Asui is one of the side characters in My Hero Academia, and it is quite natural that the lion's share - or perhaps the frog's share - of the spotlight would not fall on her. However, that had never truly seemed the case at the beginning. Tsuyu played important roles in the first few arcs of the story, and since her introduction has drawn attention because of her easygoing nature, interesting skillset and overall character design.
However, over time, Tsuyu Asui has been slowly relegated to the side with her character often being seen in the background in both the anime and manga. As such, it is necessary to look at if the manga had squandered this Class 1A student's potential over time.
Tsuyu Asui's hidden potential in My Hero Academia makes her an underrated character
Asui is agile and mobile, and thanks to her Quirk, she can jump higher and higher. She may not be physically strong, but her quick reflexes make her difficult to catch. When required, she can hold her own and wear down her opponent.
In My Hero Academia, for aspiring heroes, the internship and work-study term represents significant growth. Asui could have easily faded into the background at this stage because there were so many internships and tales going on, but she made amazing progress and even defeated a villain on her own in her own OVA.
The biggest impediment to the further development of Tsuyu's Quirk is that, with the exception of Himiko Toga and Mirko, most of the My Hero Academia female characters are not given much of a fighting role by the series' creator, Kohei Horikoshi. Tsuyu has already shown that she is capable of tremendous things if given the chance.
With a few notable exceptions, most women characters in shonen series are reduced to supporting or weaker roles. This is also true of Horikoshi's female characters. Tsuyu Asui, who already has a minor role among the girls, is given even less attention in Horikoshi's My Hero Academia.
Tsuyu is incredibly adaptable. She has the ability to blend in with her surroundings, make long jumps, cling to walls, produce mild toxins and paralysing substances, and maybe most infamously, grip or fling humans with her incredibly long tongue. Her strong tongue strongly implies that Tsuyu has superhuman strength as a result of her Quirk, which would be yet another talent she possesses.
However, while playing an important role in the first season, Tsuyu failed to have any significant feats following that. While highlighting her potential as a strategist in the Sports Festival, she failed to qualify for the finals. She took on a major role in Uraraka's fight with Himiko Toga, but did not participate in Bakugo's retrieval in My Hero Academia.
While she does secure an internship during the fight with Overhaul and his yakuza gang, her achievements along with those of her mentor and Uraraka were shoehorned off-screen. She played a part in helping Deku realize his place among his friends at the end of the Dark Deku arc, but this role was mostly as a side character and not as a major focus of the episode.
It is undeniable that Horikoshi used Tsuyu's introduction to show off a unique character, but he did not explore it to the fullest. Her potential remains untapped, in the absence of which, she might have rivalled the top students of her class.