I would nominate @timcliff, @elear, @jesta, @transisto and @fulltimegeek.
Let me explain why I am nominating these guys. The first three are top developers. The foundation should have skilled individuals at the top of it.
The other two are whales. If the foundation doesn't have proper representation of large stakeholders, a conflict of interest may arise. It should have both devs and whales. It also should include some critics and steem enthusiasts (not nominating any new names since many of them were already nominated by others).
Edit: I would also like to nominate the following witnesses: