Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
Neji might gain a significant boost in power. Without the seal suppressing him, his chakra flow could become more natural and stronger. He could potentially unlock new abilities or improve his existing ones, like his Gentle Fist technique becoming even more potent.
In fanfiction, Naruto might remove the curse seal through intense training. He could focus his chakra in a new way to counteract the dark energy of the curse seal. For example, he might use Sage Mode training to purify his chakra system and gradually force out the curse seal's influence.