Board Thread:Theories and Speculation/@comment-32742265-20180119154238/@comment-6769189-20180126001433

But Sasuke did copy Lee's taijutsu, with an incomplete Sharingan mind you. He may have not been able to do it as fast but he still did it with like, no practice. Chakra reserves seem like the only real limitation. The manga says it can copy anythig it sees but never stated the user cant copy am unknown transformation.

Who is to say the Uchiha don't know a few jutsu per nature transformation. As we have seen with Kakashi, characters have a certain transformation they specialize and prefer over others.