I would characterize him as a bad engineer. Which for a CEO is a lot better than nothing, if one does not become too arrogant and stops listening. Which, by now he seems to have done. He clearly can do the math of rocket science, but that math is not actually super hard, but its still better than your average CEO he can do. He can understand math and physics based arguments.

But he has never understood people, politics, etc. Which is what twitter is all about.