How would he be rank wise? Do you think he'd be anywhere near as proficient as he is now? He'd just be an average ninja, I would say he would be fodder to be honest.
It would definitely make him weaker. It's not like he depends on it like sasuke. But every fight he has ever been in since Zabuza he pulls it out before the fight. He reads people's movements with it and there hand signs making him faster being able dodge better
He was a jonin before the Sharingan. He graduated the Academy very early and joined the ANBU at a young age. He was by no means fodder. Without Obito's eye, idt he'd be any weaker. He would just have to train more with the jutsu he knows, like every other character.
Kakashi mannaged to become a jounin at a young age before he got his sharingan .. + he's the son of the legendary white fang I think he'd be high jounin lvl / low kage lvl for sure ..