If things that have happened to Kakashi and Obito have been different, Kakashi probably would still be a strong shinobi even without sharingan.
Before Obito's loss and Rin's death, Kakashi was a very competitive guy, he want's to prove people that he was a better shinobi than his father, he became jonin at 13, he developed his own jutsu at a very young age, no one aside from him has done that in the manga. But after the losses he had in his life, he also lost his motivation, he became the laid back guy we know of.