Personally, Shinobi that are very versatile in their fighting style could find some Sharingan very beneficial. Shinobi like Rock Lee can't make too much use since he only has Taijutsu, but someone like Naruto could make use of it. Naruto being a Ninjutsu and Taijutsu user, his weakness of not being able to do Genjutsu can be fixed with some Sharingan. Not to mention if he can copy different Jutsu, he'd be a way stronger Shinobi overall. So in my opinion, Naruto would be overpowered with Sharingan. Nine tails and the Sharingan sounds pretty devastating. Who do you think could be overpowered with some Sharingan?
Lee could use the Sharingan's analytic prowess to help with his Taijutsu. His speed, eight gates, and predictive capabilities would make him an overpowered Taijutsu fighter, who would be almost impossible to dodge. Naruto also fits this category. The biggest would probably be Hashirama, Tobirama, Orochimaru, Jiraiya, Tsunade, Sakura, Gai, Hiruzen, and any Jinchuriki to help control their Bijuu more effectively.
Rock Lee's Taijutsu plus the predictive powers of a Sharingan? Who could stop him?
Minato maybe? He moves so fast all the time, so maybe the Sharingan helping him predict movements would make him even more deadly. Like, who could keep up with both his speed and predictive capabilities?
Maybe Sakura would be able to be a more equally notable part of Team 7 if she had the Sharingan. Someone with her strength and the Sharingan to back up the Taijutsu would be cool.
EDIT: Imagine the Raikages. Their speed. Plus Sharingan's prediction and cognition. I daresay they'd be untouchable by anyone less than Hashirama.