While Dragon Ball has focused on the growth of Goku and Vegeta, and all the other characters have faded into the background in terms of character development and increasing the level of strength, Gohan has proved that he is also worthy of attention — something that was highlighted in one of the Dragon Ball spin-offs, which proves that Gohan is absolutely useless in Dragon Ball Super.
Gohan is Goku’s eldest son, and during the Dragon Ball Z Cage Games Saga, he really proved himself as a powerful asset of the Z Fighters team, since it was during this storyline that Gohan first achieved Super Saiyan. . Since then, Gohan has mostly taken his mind off the battles, doing so reluctantly every time the fate of the world is at stake. The most recent example of Gohan joining other Z fighters in battle was during the Dragon Ball Super Strength Tournament, during which Gohan revealed that he had officially stopped relying on the inner strength of his Saiyan heritage to discover new forms of strength, and would instead only focus on creating parts of him that they were human.
In Super Dragon Ball Heroes: Dark Demon Realm Mission! Chapter 13 Yoshitaka Nagayama, an alternate version of Gohan (known as Xeno Gohan) joined the interdimensional police known as the Time Patrol. Their mission is to prevent the Dark Empire from leaving the Realm of Dark Demons and poisoning the mortal realm with their evil energy. In this chapter, Xeno Gohan and Xeno Goku from the Time Patrol, along with other participants, including Vegeta, Goten and Thranx, went to the Dragon Ball GT universe to prevent the Dark Empire from attacking this timeline. Unfortunately, the Time Patrol failed to contain the evil influence of the Dark Empire, and one of their soldiers was able to infect Super Saiyan 4 Gogeta, turning him into a terrifyingly powerful monster known as the Dark Gogeta. To fight this enemy, Xeno Goku and Xeno Vegeta merged and became Xeno Gogeta before strengthening Super Saiyan 4 themselves. However, even that wasn’t enough to stop Dark Gogeta, so Xeno Gohan found a way to unlock Super Saiyan 4 himself and joined his father and Vegeta in their battle to stop this one an almost invincible villain.
This chapter of Super Dragon Ball Heroes proves that Gohan has the power to reach Super Saiyan 4 after controlling his great ape form and using its power. Gohan has never possessed so much energy, and in Dragon Ball Super he never will. Super Saiyan 4 is the crudest form of Saiyan power as it is derived from their most animalistic transformation. Since Gohan abandoned his Saiyan heritage in Dragon Ball Super, he will never have the power that his Xeno counterpart possessed, which is a complete waste of time, as his “Time Patrol” variant proves that Gohan is capable of becoming as powerful as his father if he would just accept every aspect myself.
Now, in defense of Dragon Ball Super, the transformation of Super Saiyan 4 is not canon in the Dragon Ball universe, as no one in the main continuity has ever unlocked it, so it is unclear if Gohan will be able to achieve Super Saiyan 4 in Dragon Ball Super at all, as it is unclear if this transformation is possible at all. However, the fact that his colleague from the Time Patrol was strong enough to use the power associated with this form proves that Gohan is much stronger than he has not yet been depicted in the current continuity, which in any case proves that Gohan is waiting for his potential in the Dragon. Ball is Super without using all the power capabilities available to him as a Saiyan warrior.