Saint doesn’t want it. He told Executor Hideo as much during Splicer. I don’t think Shaxx would want it either. To be honest, it’s a lot like being President. If you actually WANT to hold such a stressful and thankless office, there’s something wrong with you and you probably shouldn’t hold it. When Zavala is gone I fear it may break Ikora. There may not even be a Vanguard by the end of everything. Fortunately we don’t totally need one, as there are lots of folks already good at running ops for us. Oh and the only logical choice for Vanguard is Osiris, as he was head of it before Zavala.