He'd probably still be known as The Copy Ninja. And yes, I believe he is strong enough to become an Akatsuki member (especially know that he knows how to use Kamui) but he never would have been able to join the organization considering that Obito was spearheading the operation behind the scenes. I kinda doubt Obito would've let Kakashi join Akatsuki because that could've contributed to his identity being discovered long before his plan was in motion.