My Hero Academia brings complex family dynamics and notions of redemption, especially in the journey of Shoto Todoroki. Shoto's character development began with dealing with his traumatic past and reconciling with his family, especially his father, Endeavor.
His journey towards self-acceptance and forgiveness was essential in amplifying his narration and helping close the turbulent past of the Todoroki family. However, Dabi's self-destructive plan would have undermined all the growth Shoto had faced and the redemption of the family by destroying everything that had so far been conquered.
Disclaimer: This article contains spoilers for the manga. Any opinion expressed here belongs to the author and not Sportskeeda as a whole.
Dabi's self-destruction plan could have turned Shoto's arc meaningless in My Hero Academia

If Dabi had commited the ultimate act of self-sacrifice by blowing himself up, it would have gone a long way to undermine the potency of Shoto Todoroki's character arc in My Hero Academia. A large part of Shoto's arc relates to reconciliation with his family, particularly with Dabi, whose trail of destruction embodies the darkest aspects of the Todoroki legacy.
Shoto's motivation to fight Dabi is his desire to stop his brother from causing further damage and more bloodshed has to confront some excruciating truths of their past and attempts to mend the broken family.
By taking away from Shoto the chance to save or reach Dabi, the emotional and thematic meaning of Shoto's journey would have been irreparably damaged. Shoto's conflict, motivated, as it's now, to put an end to the cycle of pain for himself and his family, would seem entirely meaningless.

Most of the emotional weight would be drained from their final confrontation, and Shoto's declaration about his love for his family would be less than convincing. Had Dabi, instead of meeting Todoroki, resorted to self-annihilation, Shoto would have missed the opportunity for a real victory, a hero’s choice defined by his own ideals rather than his family’s legacy.
Shoto's growth needs knowledge of trauma in the history of his family, dealing with the crimes of his father Endeavor, and acknowledging the complexity of the suffering. Confronting Dabi would force Shoto to face raw traumas and come out as a hero, standing well beyond Endeavor's shadow.

Dabi's Death would snatch away the cathartic resolution from Shoto, letting him mourn the death of a family member who succumbed to bitterness instead of painful yet necessary acceptance of Dabi's suffering. Without that encounter, Shoto wouldn't have gotten the psychological closure necessary to learn the story about his family.
Dabi's grudge against Endeavor and personification of unrelenting anger would make the choices the two brothers made contrasting in response to trauma. Shoto’s resilience and willingness to transcend hatred wouldn't be quite so poignant if Dabi's story were to end in self-destruction.

This is very important to the confrontation Shoto needs with his family's darkness, internalizing compassion and duty to finally truly break the cycle of resentment. The Todoroki family’s journey of healing would have also remained incomplete without a final, reconciliatory confrontation with Dabi. The Todoroki family has been working toward understanding and forgiveness, with Endeavor attempting to atone for his past mistakes.
Dabi’s stubbornness and refusal to accept this healing pushes the family to confront their history. Dabi’s self-destructive choice would have cut this arc short, preventing Shoto, Endeavor and Rei from reckoning fully with their mistakes and the pain they’ve caused.
Final thoughts
Dabi's self-destruct plan would have devalued Shoto Todoroki's arc in My Hero Academia drastically because the emotional take from his process would have been wiped out completely.
Shoto's character progression is built around facing family trauma, especially with Dabi, and trying to end the cycle of resentment. Shoto wouldn't have had that true chance at closure and redemption and would've left the healing of the Todoroki family path incomplete.
Related links:
My Hero Academia: 8 of Dabi’s best fights, ranked