Why didn't Naruto show his full strength when he was first reborn in the dirt? Personally, I think the reason lies in the skill limitations of the rebirth of the dirt and the need for plot development, which is explained below.
From the perspective of the skill setting of the rebirth of the dirt, because the summoned person hosts the soul on the living human carrier, the configuration difference is very obvious compared with the living life, and in this case, the thousand hand pillar naturally cannot show its full strength.
Friends who are familiar with Naruto are well aware that the bloodline advantage of the bloodline boundary type accounts for a large proportion of Naruto's combat system, and if you want to play the bloodline advantage, you must rely on special carriers to achieve the role of Naruto who can have a bloodline advantage, basically through genetic genes to get part of the ability blessing effect, through the difference between the body and other characters without bloodline advantage (such as writing wheel eyes, white eyes, corpse bone veins, etc.).
Or the special chakra nature change ability, the reason why the pillar is strong in combat is also due to its own bloodline advantage.
The Thousand Hands clan is the descendant of the Six Immortals, plus the identity of the asura reincarnation between the Thousand Hands Pillar inherited the Immortal Body, so that the recovery ability of the Body of the Thousand Hands is far beyond ordinary people, and with the special Chakra Nature Change Ability, it can make the Thousand Hands Pillar use the Wooden Escape, if it is separated from the innate advantage, it is difficult to achieve the strength of the Pillar as always.
Even if the rebirth of the Dirt Earth can force the soul between the Thousand Hand Pillars on the living human carrier, the difference in ability configuration compared with the thousand hand pillar before life is still very obvious, and it is impossible for the Great Snake Pill to find a living human carrier with the same quality as the thousand hand pillar before life.
The result is that even if the rebirth of the dirt can inherit the previous skills between the Thousand Hands Pillar, because the living human carrier does not have the special physical advantages between the Thousand Hands Pillar, the actual effect of each ability is to be reduced.
From the perspective of plot development, it is impossible to make the ability of the Thousand Hands Pillar of Death and Resurrection too anti-heavenly, otherwise the three generations of Naruto would not be able to successfully seal the first generation of Naruto.
In terms of ability setting, the ability advantage of the Dirt Rebirth for the non-six-level characters is extremely obvious, and the almost infinite Chakra + the Dirt Rebirth Body that cannot be destroyed by conventional means makes ordinary ninjas almost hopeless of winning when they encounter the Dirt Rebirth Individual.
The content of the Great Snake Maru's attack on Kibamura would not have been successful according to Kishimoto's plan, and if the ability of the Thousand Hands Pillar of Rebirth in the Dirt Waster was not limited, it was unrealistic to expect the Ape Flying Sun To use the conventional Five Attributes Ninjutsu + Psychic Beast + Seal Technique and its confrontation, it had long been killed by the Thousand Hands Pillar, and it was impossible to have the opportunity to use the Ghoul Seal. Once the three generations of Naruto receive the box lunch in advance, then Naruto may have an early finale, which is obviously what Kishimoto did not want to see.
Only other means can be used to limit the exertion of the individual combat power of the reincarnated individuals in the dirt, so that Naruto's plot can develop according to the author's established ideas. Otherwise, with the bloodline advantage set between the Thousand Hands Pillar, it would be difficult for the three generations of Naruto to reverse the war situation without adding the restrictions mentioned earlier.
Of course, some people will think that the main reason why the strength between the thousand hand pillars in the early stage cannot be exerted is that the technology of rebirth in the dirt is not perfect enough, but in fact, even if the technology of rebirth in the dirt is improved, the great snake pill improves the conditions of the living carrier in the later stage, and the individuals summoned are still unable to show their peak level. Therefore, the skill setting and plot development needs of the rebirth of the dirt determine the scope of application of the rebirth of the dirt.
Finally, to sum up, the reasons that limit the rebirth of the first generation of The Dirt Naruto cannot show its full strength I personally believe that there are two main reasons: one is the restriction on the use of the skills of the Dirt Rebirth itself (the living human carrier cannot inherit the blood inheritance boundaries and genetic talents originally possessed by the original generation), and the other is the need for plot development (the ability between the Thousand Hands Pillar cannot be too strong to affect the development of the subsequent plot). Please forgive me for the place where the analysis is not in place, and if you have other ideas, please leave a message to discuss.