The potential to become a Great Emperor was not a fixed standard, but a vague concept, because there had been more than one Emperor throughout the ages.
They too had once been weak and had struggled across the river of cultivation before rising in a certain era.
Take Chaotic Ancient Emperor, for example. He went from weakness to strength, growing step by step. Only upon reaching the final stage of Quasi-Emperor did he stand shoulder to shoulder with those who had attained enlightenment throughout history, gaining the bearing of an Emperor before defying the heavens and attaining the Dao.
Then there was Great Emperor Wu Shi. He swept through everything from the very beginning, never having a weak period. Two words described him: invincible.
And then there was Ruthless Great Emperor. In her early days, she cultivated as a Mortal Body, with no scriptures and no resources. She was not much stronger than Chaotic Ancient Emperor; later, she created the Heaven-Swallowing Demon Art, attained the Dao as a Chaotic Body, and stood alongside Wu Shi. She was another extreme.
Golden-Winged Little Peng King possessed unparalleled talent and was praised by the world as having a fraction of a young Great Emperor's bearing. He never laid ambushes and always fought open, decisive battles. He forcibly challenged the Nine Heavens Pass set by the Great Saint of the Heavenly Peng Clan, only to perish in the end.
That was the lower limit of Great Emperor potential: comparable to Chaotic Ancient Emperor. If one could endure it, one might become a Quasi-Emperor; if not, at best one would become a Great Saint Realm cultivator. The worst outcome was Golden-Winged Little Peng King failing his trial.
A level above were people like Di Tian, Western Bodhisattva, and Human King... All of them could become