Contrary to popular belief, Shto Todoroki from My Hero Academia and Rock Lee from Naruto have a lot more in common. When they were first revealed, each of them had a minor air of curiosity, although many fans were unaware of them. Their big moment occurred in a game that ought to have been a non-event in the early stages of a tournament. They became one of the most adored characters in their respective shows as a result of their unexpectedly passionate clashes.
However, after that, their significance is where they start to diverge. Todoroki's position in the main plot of MHA grew in significance, whereas Rock Lee's in Naruto suffered a severe decline. What occurred with Todoroki appears to be what should have also occurred with
How much time have Shto and Rock Lee spent on the big screen?
After the UA Sports Festival Arc, Shōto would frequently appear as an important character throughout the arcs. He had key roles to play in the Vs Hero Killer Arc, the Hideout Raid Arc, the Provisional Hero License Exam Arc, the Remedial Course Arc, the Pro Hero Arc, and the Endeavor Agency Arc. He also got important roles in all three movies, as well as a leading role in the third one. Even in the arcs where he didn't get much to do, he still had a significant on-screen presence. He has practically become a tritagonist for the series alongside Deku and Bakugō.
Rock Lee's presence following the Chūnin Exams Arc left a little more to be desired. There was a significant amount of time devoted to his recovery period, which, in fairness, was still engaging. He also got a key fight in the Sasuke Retrieval Arc. After the time skip, he got some things to do in the Kazekage Retrieval Mission Arc, the Five Kage Summit Arc, and the Fourth Great Shinobi War. He also got a key fight in the third Naruto movie, Guardians of the Crescent Moon Kingdom. One could argue that he also got plenty to do in the two years of filler arcs for what they're worth. Regardless, there's still an apparent contrast between his moments in Parts I and II.
Comparing Shōto's screen time after the UA Sports Festival to Lee's time after the Chūnin Exams really puts Lee's problem into perspective. While Shōto continued to become relevant throughout MHA, including the Filler material, Lee was narratively left to languish on the sidelines of Naruto. This isn't even accounting for their place in their respective series' final war arcs, which Shōto is currently upstaging Lee in. Perhaps there's something about how their two series unfolded that led to this difference.
Did Shto and Rock Lee's Stories Affect the Development of Their Characters?
What kept Shōto so central to the plot of MHA was his relationship with Endeavor, the second-best Hero in Japan. He was raised by his father to be a Hero who could surpass All Might, the best Hero in Japan and the world. Unfortunately, Endeavor's obsession with surpassing All Might caused him to neglect and even abuse his family; he even drove his wife insane and his first son Tōya to villainy. Thus, the Todoroki family drama has become one of the central plot points in the series, especially as it concerns Endeavor, Shōto, and Tōya.
Lee and the rest of Team Guy should have been able to have a similar level of influence on Naruto's overarching Narrative. Unfortunately, a lot of the screen time that Lee earned for them in Part I was given over to Might Guy. Even if Guy and Lee had switched roles, the story might not have worked. It's cool that a supporting character like Guy got as much attention as he did, but it shouldn't have come at the cost of the attention Lee and the others deserved.
What happened to Shōto might have been a nice fate for Lee. In another version of the story, Naruto and the rest of Team Kakashi could have seen more of Lee and the rest of Team Guy past the Kazekage Retrieval Mission Arc; Lee might have even gotten to fight one of the Akatsuki. In a way, Shōto's popularity and relevance in MHA could be seen as a sort of reflection of Lee's potential in that other version of Naruto. At the very least, Lee still has his spin-off to fall back on.