Ivan the 4th, definitely would be nice to see, completely psychotic later years Ivan IV that is. For the Chinese I really have to lean to Cao Cao. He fits in a period when no other leaders were around and Den Xiaoping is far too close to Mao in the timeline.
I applaud your pre-20th century choices!
Given the copious number of times I have posted in these kinds of threads, it is probably obvious why.